This service manual provides servicing and maintenance information for Caterpillar lift trucks powered by GM 4.3L gasoline engines and Mitsubishi S6S diesel engines. The manual covers GP40K, GP40KL, GP45K, GP50K, DP40K, DP40KL, DP45K, and DP50K models, providing specifications, component locations, safety procedures, and other technical details needed for repair and maintenance of these trucks. Safety warnings indicate potential hazards and direct the user to read all instructions before working on the trucks.

1. Service Manual
99739-66100
For use with GM4.3L, S6S
Engine Service Manual
GP40K, GP40KL, GP45K, GP50K;
DP40K, DP40KL, DP45K, DP50K
Chassis & Mast
GP40K ET29B-00011-up DP40K ET19C-00011-up
GP40KL ET29B-50001-up DP40KL ET19C-50001-up
GP45K ET29B-80001-up DP45K ET19C-80001-up
GP50K ET33A-50001-up DP50K ET28B-50001-up

2. FOREWORD
This service manual is a guide to servicing of Caterpillar® Lift Trucks. The instructions are
grouped by systems to serve the convenience of your ready reference.
Long productive life of your lift trucks depends to a great extent on correct servicing – the
servicing consistent with what you will learn from this service manual. We hope you read the
respective sections of this manual carefully and know all the components you will work on
before attempting to start a test, repair or rebuild job.
The descriptions, illustrations and specifications contained in this manual were of the trucks of
serial numbers in effect at the time it was approved for printing. Caterpillar reserves the right
to change specifications or design without notice and without incurring obligation.
GP40K, GP40KL, GP45K, and GP50K are powered by GM4.3L gasoline engine.
DP40K, DP40KL, DP45K, and DP50K are powered by Mitsubishi S6S diesel engine.
Pub. No. 99739-66100
Safety Related Signs
The following safety related signs are used in this service
manual to emphasize important and critical instructions:
Indicates a specific potential hazard
resulting in serious bodily injury or
death.
Indicates a specific potential hazard
resulting in bodily injury, or damage
to, or destruction of, the machine.
Indicates a condition that can cause
damage to, or shorten service life of,
the machine.
NOTE
CAUTION
WARNING

3. HOW TO READ THIS MANUAL
Disassembly diagram (example)
Sequence
1. Cover, Bolt, Washer (part name)
2. Output shaft (part name)
Suggestion for disassembly
(1) Output shaft removal
Symbols or abbreviations
OP ...................Option
R1/4.................Taper pipe thread (external) 1/4 inch (formerly PT1/4)
Rc1/8...............Taper pipe thread (internal) 1/8 inch (formerly PT1/8)
G1/4A..............Straight pipe thread (external) 1/4 inch (formerly PF1/4-A)
Rp1/8...............Straight pipe thread (internal) 1/8 inch (formerly PS1/8)
Unit: mm (in.)
A
0.020 to 0.105
Clearance between
(0.00079 to 0.00413)
cylinder and piston 0.15
B
(0.0059)
A: Standard value B: Repair or service limit
Disassembly sequence
Each disassembly diagram is followed by
Disassembly sequence and Suggestions for
disassembly.

4. 4. Lower the forks or other implements to the ground
before performing any work on the truck. If this
cannot be done, make sure the forks or other
implements are blocked correctly to prevent them
from dropping unexpectedly.
5. Use steps and grab handles (if applicable) when
mounting or dismounting a truck. Clean any mud
or debris from steps, walkways or work platforms
before using. Always face truck when using
steps, ladders and walkways. When it is not
possible to use the designed access system,
provide ladders, scaffolds, or work platforms to
perform safe repair operations.
6. To avoid back injury, use a hoist when lifting
components which weigh 23 kg (50 lb.) or more.
Make sure all chains, hooks, slings, etc., are in
good condition and are of the correct capacity. Be
sure hooks are positioned correctly. Lifting eyes
are not to be side loaded during a lifting
operation.
7. To avoid burns, be alert for hot parts on trucks
which have just been stopped and hot fluids in
lines, tubes and compartments.
8. Be careful when removing cover plates.
Gradually back off the last two bolts or nuts
located at opposite ends of the cover or device and
pry cover loose to relieve any spring or other
pressure, before removing the last two bolts or
nuts completely.
9. Be careful when removing filler caps, breathers
and plugs on the truck. Hold a rag over the cap or
plug to prevent being sprayed or splashed by
liquids under pressure. The danger is even greater
if the truck has just been stopped because fluids
can be hot.
The serviceman or mechanic may be unfamiliar with
many of the systems on this truck. This makes it
important to use caution when performing service
work. A knowledge of the system and/or components
is important before the removal or disassembly of any
component.
Because of the size of some of the truck components,
the serviceman or mechanic should check the weights
noted in this Manual. Use proper lifting procedures
when removing any components.
Following is a list of basic precautions that should
always be observed.
1. Read and understand all warning plates and decals
on the truck before operating, lubricating or
repairing the product.
2. Always wear protective glasses and protective
shoes when working around trucks. In particular,
wear protective glasses when pounding on any
part of the truck or its attachments with a hammer
or sledge. Use welders gloves, hood/goggles,
apron and other protective clothing appropriate to
the welding job being performed. Do not wear
loose-fitting or torn clothing. Remove all rings
from fingers when working on machinery.
3. Do not work on any truck that is supported only
by lift jacks or a hoist. Always use blocks or jack
stands to support the truck before performing any
disassembly.
SAFETY
WARNING
The proper and safe lubrication and
maintenance for this lift truck, recommended
by Caterpillar, are outlined in the
OPERATION & MAINTENANCE MANUAL for
these trucks.
Improper performance of lubrication or
maintenance procedures is dangerous and
could result in injury or death. Read and
understand the OPERATION &
MAINTENANCE MANUAL before performing
any lubrication or maintenance.
WARNING
Do not operate this truck unless you have
read and understand the instructions in the
OPERATION & MAINTENANCE MANUAL.
Improper truck operation is dangerous and
could result in injury or death.
WARNING

5. 10. Always use tools that are in good condition and
be sure you understand how to use them before
performing any service work.
11. Reinstall all fasteners with same part number.
Do not use a lesser quality fastener if
replacements are necessary. Do not mix metric
fasteners with standard nuts and bolts.
12. If possible, make all repairs with the truck
parked on a level, hard surface. Block truck so it
does not roll while working on or under truck.
13. Disconnect battery and discharge any capacitors
(electric trucks) before starting to work on truck.
Hang “Do not Operate” tag in the Operator’s
Compartment.
14. Repairs, which require welding, should be
performed only with the benefit of the
appropriate reference information and by
personnel adequately trained and knowledgeable
in welding procedures. Determine type of metal
being welded and select correct welding
procedure and electrodes, rods or wire to provide
a weld metal strength equivalent at least to that
of parent metal.
15. Do not damage wiring during removal
operations. Reinstall the wiring so it is not
damaged nor will it be damaged in operation by
contacting sharp corners, or by rubbing against
some object or hot surface. Do not connect
wiring to a line containing fluid.
16. Be sure all protective devices including guards
and shields are properly installed and functioning
correctly before starting a repair. If a guard or
shield must be removed to perform the repair
work, use extra caution.
17. Always support the mast and carriage to keep
carriage or attachments raised when maintenance
or repair work is performed, which requires the
mast in the raised position.
18. Loose or damaged fuel, lubricant and hydraulic
lines, tubes and hoses can cause fires. Do not
bend or strike high pressure lines or install ones
which have been bent or damaged. Inspect lines,
tubes and hoses carefully. Do not check for
leaks with your hands. Pin hole (very small)
leaks can result in a high velocity oil stream that
will be invisible close to the hose. This oil can
penetrate the skin and cause personal injury. Use
cardboard or paper to locate pin hole leaks.
19. Tighten connections to the correct torque. Make
sure that all heat shields, clamps and guards are
installed correctly to avoid excessive heat,
vibration or rubbing against other parts during
operation. Shields that protect against oil spray
onto hot exhaust components in event of a line,
tube or seal failure, must be installed correctly.
20. Relieve all pressure in air, oil or water systems
before any lines, fittings or related items are
disconnected or removed. Always make sure all
raised components are blocked correctly and be
alert for possible pressure when disconnecting
any device from a system that utilizes pressure.
21. Do not operate a truck if any rotating part is
damaged or contacts any other part during
operation. Any high speed rotating component
that has been damaged or altered should be
checked for balance before reusing.

6. Model View
Truck Models Covered
This Service Manual furnishes servicing and maintenance
information for the following trucks:
1-1
GENERAL INFORMATION
103235
Truck model Model code – Serial number Engine mounted
GP40K ET29B – 00011- up GM4.3L gasoline engine
GP40KL ET29B – 50001- up GM4.3L gasoline engine
GP45K ET29B – 80001- up GM4.3L gasoline engine
GP50K ET33A – 50001- up GM4.3L gasoline engine
DP40K ET19C – 00011- up Mitsubishi S6S diesel engine
DP40KL ET19C – 50001- up Mitsubishi S6S diesel engine
DP45K ET19C – 80001- up Mitsubishi S6S diesel engine
DP50K ET28B – 50001- up Mitsubishi S6S diesel engine

7. Serial Number Locations
1-2
GENERAL INFORMATION
Name plate
(Gasoline- and LP-Gas-
engine models)
Chassis serial number
(Diesel-engine models)
(Gasoline- and LP-Gas-engine models)
(Diesel-engine models)Transmission serial numberMast serial number
Engine serial number
208804

8. 1-3
GENERAL INFORMATION
Chassis and Mast Model Identification
[Chassis]
GP 40 K
Generation designator
Maximum capacity/Load center
40: 4000 kg (8000 lb)/500 mm (20 in.)
40L: 4000 kg (8000 lb)/600 mm (24 in.)
45: 4500 kg (10000 lb)/600 mm (24 in.)
50: 5000 kg (11000lb)/600 mm (24 in.)
Maximum lifting height
[“33” stands for 3300 mm (130 in.)]
Order of the minor change
(“A” for the original, “B” for the first change, “C” for
the second change, and so on)
Applicable truck model designation
40: 4 ton class
40L: 4 ton class
45: 4.5 ton class
50: 5 ton class
Kind of mast
V: simplex mast
F: duplex mast
M: triplex mast
Major change
(“2” for the original, “3” for the first change, and so
on up to “9”)
Engine type
GP: gasoline engine type
DP: diesel engine type
[Mast]
4 V 40 A 33

9. Dimensions
1-4
GENERAL INFORMATION
G K C L
B
H
A
J
E
I
P
M
F
OND
202762A

10. 1-5
GENERAL INFORMATION
Ref. Truck Model GP40K GP40KL GP45K GP50K
No. Item DP40K DP40KL DP45K DP50K
A Maximum lift 3300 (130)
B Free lift 150 (5.9) 160 (6.5)
C Fork spread (outside) 300 to 1190 (12 to 47)
D Fork length 1220 (48)
E Tilt angle (forward – backward) 6° – 10°
F Overall length
4290 4340 4395 4525
(168.9) (170.9) (173.0) (178.2)
Single tire 1415 (55.7) 1460 (57.5)
G Overall width (outside of tires)
Dual tire 1780 (70.1) 1965 (77.4)
H Overall height (to top of mast lowered) 2320 (91.5) 2400 (94.5)
I Overall height (to top of overhead guard) 2250 (88.6)
J Overall height (mast extended) 4430 (174.4) 4580 (180.5)
Single tire 1175 (46.5)
K Tread (front)
Dual tire 1310 (51.5)
L Tread (rear) 1180 (46.5)
M Wheelbase 2000 (78.5) 2150 (84.5)
N Front overhang 557 (21.9) 562 (22.1) 582 (22.9)
O Rear overhang 513 (20.6) 563 (22.6) 613 (24.4) 573 (22.6)
P Underclearance (at frame) 252 (9.9)
Unit: mm (in.)

11. Technical Data
1-6
GENERAL INFORMATION
Truck Model
GP40K GP40KL GP45K GP50K
Item
DP40K DP40KL DP45K DP50K
Model code GP: ET29B GP: ET33A
DP: ET19C DP: ET28B
Type Standard
Capacity/load center 4000/500 4000/600 4500/600 5000/600
kgf/mm (lbf/in.) (8000/20) (8000/24) (10000/24) (11000/24)
Maximum lift mm (in.) 3300 (130)
Lift speed (rate load) GP: 510 (100) GP: 440 (87) GP: 430 (85)
mm/sec (fpm) DP: 500 (98) DP: 430 (85) DP: 420 (83)
Lowering speed (rate load)
500 (100)
mm/sec (fpm)
Tilt angle (forward – backward) 6° – 10°
Free lift mm (in.) 150 (5.9) 160 (6.5)
Travel speed of Forward 19.5 (12) 23.5 (15)
powershift
transmission models
km/h (mph) Reverse 19.5 (12) 23.5 (15)
Minimum turning radius 2735 2775 2820 2965
mm (in.) (107.7) (109.3) (111) (116.7)
Inside 83°
Steering angle
Outside 56°33’
Minimum Single tire 2390 (94.1) 2430 (95.7) 2450 (96.5) 2510 (98.8)
intersecting aisle
mm (in.) Dual tire 2570 (101) 2590 (102) 2620 (103) 2670 (105)
Front tires
Single tire
8.25-15-14PR (I) 300-15-18PR (I)
(size and inflation 785 (8.0) [114] 785 (8.0) [114]
pressure)
Dual tire
7.50-16-12PR (I)
kPa (kgf/cm2
) [psi] 686 (7.0) [99.5]
Rear tires (size and inflation
7.00-12-14PR (I)
pressure) kPa (kgf/cm2
) [psi]
686 (7.0) [99.5] 834 (8.5) [121]
Single drive tire (unloaded) GP: 5630 (12400) GP: 6030 (13300) GP: 6600 (14500) GP: 7080 (15600)
kg (lb) DP: 5710 (12600) DP: 6120 (13500) DP: 6680 (14700) DP: 7160 (15800)
Dual drive tire (unloaded) GP: 5810 (12800) GP: 6160 (13600) GP: 6730 (14800) GP: 7250 (15900)
kg (lb) DP: 5900 (13000) DP: 6250 (13800) DP: 6820 (15000) DP: 7320 (16100)
GeneralPerformanceTiresTruckweight

12. 1-7
GENERAL INFORMATION
Truck Model
GP40K GP40KL GP45K GP50K
Item
Engine model GM4.3L
Manufacturer General Motors
Type Gasoline
Cooling system Water cooled
No. of cylinders – arrangement 6 – 90° V
No. of strokes 4
Type of combustion chamber Semi -spherical
Valve arrangement Overhead
Type of cylinder liners Integral
Cylinder bore × stroke 101.6 × 88.39
mm (in.) (4.00 × 3.48)
Displacement cc (cu in.) 4293 (262)
Compression ratio 9.2 : 1
Rated output kW/rpm 69.5/2450
Maximum torque
305 (31.0) [224]/1200
N·m (kgf·m) [lbf·ft]/rpm
Low idle engine speed rpm 750
High idle engine speed rpm 2450
Dimensions (L × W × H) 710 × 620 × 740
mm (in.) (28.0 × 24.4 × 29.1)
Weight kg (lb) 260 (573)
Installation position Rear
Ignition Spark
Firing order 1 – 6 – 5 – 4 – 3 – 2
Initial ignition timing
0° Gasoline/ 8° L.P.G.
BTDC deg
Fuel tank capacity
115 (30)
liter (U.S. gal)
Engine(gasolineandLP-gas)

13. 1-8
GENERAL INFORMATION
Truck Model
GP40K GP40KL GP45K GP50K
Item
Ignition
Type Mold
coil
Manufacturer AC Delco
Type Pointless
Distributor
Manufacturer AC Delco
Type of spark
Internal solid state circuit
advance control
Model #41-932
Manufacturer AC Delco
Spark plug
Size mm (in.) 14 (0.55)
Gap mm (in.) 1.24 (0.0488)
Type 1FZ
Carburetor
Manufacturer AISAN Kogyo Co.
Type Electromagnetic
Fuel pump
Manufacturer Jidosha Kiki
Type × Number Cyclone with paper element × 1
Manufacturer Nippon Rokaki
Type Pressure feed
Oil pump Gear pump
Oil filter Paper element
Oil cooler Oil to water type
Oil pan
4.2 (1.1)
liter (U.S. gal)
Refill Oil filter & cooler
0.8 (0.2)
capacities liter (U.S. gal)
Total
5.0 (1.3)
liter (U.S. gal)
EnginelubricationsystemFuelsystemIgnitionsystemAircleaner

14. 1-9
GENERAL INFORMATION
Truck Model
GP40K GP40KL GP45K GP50K
Item
Type Forced circulation
Radiator Corrugated fin with pressure type
Refill capacity liter (U.S. gal) 17.2 (4.5)
Water pump Centrifugal type driven by V-belt
Thermostat Wax type
Type × number 48D26L
Voltage V 12
Capacity AH (5 Hr) 50
Type 3-phase AC
Manufacturer MANDO
Rated output V – A 12 – 50
Regulator Built-in IC type
Type Electromagnetic
Manufacturer Delco Remy
Voltage – output V – kW 12 – 0.75
BatteryAlternatorCoolingsystemStarter

15. 1-10
GENERAL INFORMATION
Truck Model
DP40K DP40KL DP45K DP50K
Item
Engine model S6S
Manufacturer Mitsubishi Heavy Industries, Ltd.
Type Water-cooled, 4-stroke cycle
No. of cylinders – arrangement 6 – in-line
Type of combustion chambers Swirl
Valve arrangement Overhead
Type of cylinder liners Dry
Bore × stroke mm (in.) 94 × 120 (3.70 × 4.72)
Displacement cc (cu in.) 4996 (305)
Compression ratio 22 : 1
Rated output kW/rpm 62.5/2450
Maximum torque
250 (25.5) [184]/1600
N·m (kgf·m) [lbf·ft]/rpm
Dimensions (L × W × H) 907.5 × 639 × 801
mm (in.) (35.7 × 25.2 × 31.5)
Weight (service) kg (lb) 350 (771)
Installation position Rear
Intake
Open BTDC deg 30°
valves
Close ABDC deg 50°
Exhaust
Open BBDC deg 74°
valves
Close ATDC deg 30°
Intake valves
Valve mm (in.)
clearance 0.25 (0.0098)
(at cold) Exhaust valves
mm (in.)
Ignition Compression
Firing order 1 – 5 – 3 – 6 – 2 – 4
Ignition or injection timing
19°
BTDC deg
Engine(diesel)

16. 1-11
GENERAL INFORMATION
Truck Model
DP40K DP40KL DP45K DP50K
Item
Fuel tank capacity
115 (30)
liter (U.S.gal)
No-load minimum speed rpm 650
No-load maximum speed rpm 2450
Type Bosch
Manufacturer Nippon Denso
Fuel
injection Plunger diam.
6.5 (0.256)
pump mm (in.)
Cam lift (one side)
6 (0.24)
mm (in.)
Type Throttle
Fuel Spray holes diam.
1.0 (0.04)
injection mm (in.)
nozzles
Injection pressure
1372 (140) [1992]
kPa (kg/cm2
) [psi]
Type Sheathed
Glow plugs
Voltage – current
22 – 4.4
V – A
Type Plunger
Fuel pump
Manufacturer Nippon Denso
Type × number Cyclone with paper element × 1
Air cleaner
Manufacturer Nippon Rokaki
Type Pressure feed
Oil pump Trochoid type
Oil filter Paper element type
Refill
Oil pan 11 (2.9)
capacities
liter
Oil filter 1 (0.3)
(U.S. gal)
Total 12 (3.2)
Engine(diesel)FuelsystemLubricationsystem

17. 1-12
GENERAL INFORMATION
Truck Model
DP40K DP40KL DP45K DP50K
Item
Type Forced circulation
Radiator Corrugated fin with pressure cap
Refill capacity
liter (U.S. gal)
14.7 (3.9)
Water pump Centrifugal type driven by V-belt
Thermostat Wax type
Type × number 48D26R × 2
Voltage V 24
Capacity Ah 50
Alternator type 3-phase AC
Manufacturer
Mitsubishi Electric Corporation
Capacity V – A 24 – 35
Voltage/current regulator Built-
IC type
Type Electromagnetic
Manufacturer Mitsubishi Electric Corporation
Voltage – output V – kW 24 – 5
Control
Manufacturer Shin Dengen Kogyo
timer
Setting sec 5 to 7
Operating voltage
16 to 30
Stop
V
solenoid
Rated current
11.3
(at 24 V) V
Manufacturer
Mitsubishi Electric
Corparation
Detector
(magnetic Output mA 180 minimum
CoolingsystemBatteryAlternatorandregulatorStarterEnginestopdevice
Transmission
cooling
Water
cooling
Oil
cooling

18. 1-13
GENERAL INFORMATION
Truck Model
GP40K GP40KL GP45K GP50K
Item
DP40K DP40KL DP45K DP50K
Type Dry, single disc (OP: wet type)
Clutch
(DP40K thru
Facing (OD × ID), 325 × 210 (12.8 × 8.3)
DP45K)
mm (in.) [wet: 325 × 225 (12.8 × 8.9)]
Material DR-8 (wet: cork)
Type 3-element, 1-stage, 2-phase
Torque Manufacturer’s
Okamura M15
converter model
Stall torque ratio 3.2
Control and
Hydraulic and column shift
shift
Powershift
Forward 4.044
F1: 5.735
transmission F2: 3.239
Ratios
Reverse 4.057
R1: 5.735
R2: 3.239
Type Synchro-mesh
Shift Floor-shift
Manual
transmission Forward
1st 8.462
(DP40K thru ratio
DP45K)
2nd 4.145
Reverse
1st 8.489
ratio
2nd 4.159
Type of gear Spiral bevel
Reduction gear
Gear ratio 4.857
Housing Banjo
Type of gear – number Straight bevel – 2
Type of pinion – number Straight bevel – 4
Powertrain
Differential

19. 1-14
GENERAL INFORMATION
Truck Model
GP40K GP40KL GP45K GP50K
Item
DP40K DP40KL DP45K DP50K
Type Recirculating ball-and-nut
Gear ratio 20.0
Steering wheel diameter
380 (15)
mm (in.)
Type Semi-integral
Power cylinder ID ×
55 × 25 (2.17 × 0.98)
rod diam. mm (in.)
Power
Effective stroke
275 (10.8)
mm (in.)
steering
Relief pressure
8336 (85 ) [1209 ]
kPa (kgf/cm2
) [psi]
Flow rate
17.5 ± 0.5 (4.6 ± 0.13)
liter (U.S. gal)/min
Front axle Full-floating tubular type
Rear axle Elliott type
Suspension
Front Fixed type
system
Rear Center-pivot type
Toe-in mm (in.) 0
Wheel
Camber 1.0°
alignment
Caster 0°
Kingpin inclination 5.0°
Type Self-adjusting, duo-servo
Drum diameter
317.5 (12.50)
mm (in.)
Lining (length × 351 × 60 × 6 − 2
Wheel width × thickness −
brakes number) mm (in.) (13.8 × 2.4 × 0.2 − 2)
Master cylinder
22.22 (0.8748) 25.4 (1.000)
ID mm (in.)
Wheel cylinder
28.58 (1.1252) 31.75 (1.2500)
ID mm (in.)
Parking
Type Mechanical, mounted on wheels
brake
Brake booster Mastervac (vacuum suspended)
Body Assembled-frame type
+ 71
0
+ 5
0
+ 490
0
BrakesystemTravelingsystemSteeringsystem
332 × 63 × 10 − 2
(13.1 × 2.5 × 0.4 − 2)

20. 1-15
GENERAL INFORMATION
Truck Model
GP40K GP40KL GP45K GP50K
Item
DP40K DP40KL DP45K DP50K
Type Gear
Manufacturer Shimazu
Hydraulic Manufacturer’s type SGP2B50L979
pump
Rated discharge
110 (29.0)/2450
liter (U.S. gal)/rpm
Drive line Universal joint
Type KVS-120VPF-2
Control Manufacturer Kayaba
valve
Relief pressure
19.1 (195) [2773]
MPa (kgf/cm2
) [psi]
Flow
Type Variable (Adjustable)
regulator
valve
Regulated flow rate
100 (26.4) 115 (30.4)
liter (U.S. gal)/min
65 70
Lift
ID mm (in.)
(2.56 ) (2.76 )
cylinders
Stroke mm (in.) 1500 (59.06)
80 90
Tilt
ID mm (in.)
(3.15 ) (3.54 )
cylinders
Stroke mm (in.) 185 (7.28)
Hydraulic tank capacity
L: 56.5 (14.9)
liter (U.S. gal)
N: 58.7 (15.5)
H: 64.4 (17.0)
+ 0.004
0
+ 0.004
0
+ 0.1
0
+ 0.1
0
+ 0.004
0
+ 0.004
0
+ 0.1
0
+ 0.1
0
Hydraulicsystem

21. Structure
8
6
9
7
9
2-1
COOLING SYSTEM
8
32
1
4
5
6
208413
208411207009
1 Engine
2 Universal joint
3 Gear pump
4 Fan belt
5 Cooling fan
6 Upper hose
7 Lower hose
8 Radiator
9 Oil cooler hoses
10 Tension pulley
1
5
10
3
2
Water
cooling
Transmission
cooling
Oil
cooling

22. Removal and Installation
Fan Belt Removal
Start by:
Remove the radiator cover.
Suggestion for removal
(1) Using a ratcheting wrench inserted in the gap between
the weight and frame, loosen the tension pulley lock
bolt by three or four turns. If the bolt is loosened
insufficiently, the tension pulley will not be moved.
(2) Move the tension pulley fully toward the fan, then
remove the belt.
2-2
COOLING SYSTEM
2
(Only loosen.)
1
3
208414
Sequence
1 Universal joint
2 Tension pulley assembly, Bolt
3 Fan belt
Tension pulley assembly
Section A–A
Tension pulley lock bolt
A
A
208415
NOTE
Do not loosen the lock bolt to such an extent that the
tension pulley would be removed.

23. Installation
Perform installation by following the removal sequence in
reverse. Also follow the instructions given below.
(1) Before installing the belt, turn the fan to check for
smooth rotation. Replace the bearing if it generates
abnormal sound.
(2) After installing the belt, push it at a point midway
between the driven and drive pulleys to make sure that
the tension pulley moves, then tighten the pulley lock
bolt firmly.
Fan Assembly Removal
Sequence
1 Fan cover
2 Fan assembly
3 Tension pulley assembly
Start by:
Remove the radiator cover.
Suggestion for removal
Remove the fan support bolts, detach the belt from the
driven pulley, and then remove the fan assembly. Place the
fan assembly with the fan support facing down and turn the
fan to check for smooth rotation. Replace the bearing if it
generates abnormal sound.
2-3
COOLING SYSTEM
3
1
2
208416

24. Installation
Perform installation by following the removal sequence in
reverse. Also follow the instruction given below.
(1) With the tension pulley lock bolt loosened, attach the
belt to the driven pulley (fan assembly pulley), then
screw in the bolt at the bottom of the fan support; do
not tighten the bolt yet. Holding the fan support by its
top, move the support until it reaches the boss (frame),
then tighten all the fan support bolts.
(2) Adjust the tension of the fan belt.
2-4
COOLING SYSTEM

25. Inspection and Adjustment
Fan belt condition
(1) Check the belt for contamination with oil, grease and/or
dust. If the contamination is slight, remove it clean
with rag or wiping paper. Do not use gasoline, oil or
any other solvent to clean the belt.
(2) During engine overhaul or belt tension adjustment,
closely check the belt for condition. Replace the belt
with a new one if it has any sort of damage.
Fan belt tension
Apply a force of 98 N (10 kgf) [22 lbf] perpendicularly to
the belt at a point midway between the fan pulley and
tension pulley. If necessary, adjust the tension by moving
the tension pulley assembly such that the belt deflects 16
mm (0.63 in) when pressed with the above force. After
adjustment, tighten the tension pulley assembly lock bolt
firmly.
Connecting Radiator Hoses
When connecting the hoses to the radiator, fit their ends
fully on the fittings and secure them with clamps. Tighten
the clamp bolts to the torques indicated below. Make sure
that each hose is correctly retained and prevented from
disconnection by the flare of the fitting.
Clamp bolt tightening torques
2-5
COOLING SYSTEM
3.92 to 5.88 N·m
Upper and lower hoses (0.4 to 0.59 kgf·cm)
[2.9 to 4.3 lbf·ft]
2.94 to 4.9 N
Cooler hose (0.3 to 0.5 kgf)
[2.2 to 3.6 lbf]

26. Coolant
Fill the radiator with coolant containing antifreeze. Start
and operate the engine to let it warm up while checking for
abnormal noise. Make sure that the quantity of coolant is as
specified by checking the level in the reserve tank.
Quantity of coolant
Radiator Cap
2-6
COOLING SYSTEM
90 ± 15 kPa
Opening pressure (0.92 ± 0.15 kgf/cm2
)
[13.1 ± 2.2 psi]
0 to 5 kPa
Vacuum valve (0 to 0.05 kgf/cm2
)
[0 to 0.73 psi]
Truck Model
GP40K, GP40KL, GP45K, GP50K DP40K, DP40KL, DP45K, DP50K
Item
Powershift transmission models Powershift transmission models
Engine 11 (2.9) 7.1 (1.9)
Radiator 4.3 (1.1) 4.7 (1.2)
Reserve tank (FULL level) 0.65 (0.17) 0.65 (0.17)
Total quantity of coolant
17.2 (4.5) 14.7 (3.9)
(including coolant in hoses)
Oil cooler 0.62 (0.16) 0.31 (0.08)
Unit: liter (U.S. gal)

27. Structure and Functions
Console Box
1 Engine coolant temperature gauge
2 Travel speed select switch
3 Fuel gauge (for diesel-engine models)
4 Service hourmeter
5 OK monitor
6 Starter switch
7 Lighting switch
8 Fuse box
9 Auto-light switch (for FC models)
3-1
ELECTRICAL SYSTEM
103249

28. OK Monitor
103239
3-2
ELECTRICAL SYSTEM
No. Indicator light OFF ON or flickering Remarks
1 Powershift transmission oil temp. indicator light Normal Overheating
2 Air cleaner element indicator light Normal Clogged Option
3 Brake fluid level indicator light Normal Low
4 Engine oil pressure indicator light Normal Low
5 Alternator not charging indicator light Normal Abnormal
6 Heater plug indicator Normal Diesel-engine
models
7 LP-Gas residual pressure alarm lamp Normal Drain water Option
8 System indicator light Normal Abnormal FC models
9 Engine coolant level indicator light Normal Low Option
Function
How to check indicator light bulbs
The bulbs are normal if all the indicator lights come ON when the starter switch key is turned to the (ON)
position. (The indicator lights will go OFF when the engine starts.)
Truck Model Indicator light No.
MC diesel-engine model 1, 2, 3, 4, 5, 6
MC LPG-engine model 1, 2, 3, 4, 5
FC diesel-engine model 1, 2, 3, 4, 5, 6, 8
FC LPG-engine model 1, 3, 4, 5, 8

29. Electrical Components Mounted on Body
3-3
ELECTRICAL SYSTEM
208773
1 Main harness
2 Fusible link (R.H.)
3 Fusible link (L.H.)
4 Fuse
5 Fuse
6 Power relay (FC model)
7 System harness
8 Harness (tilt earth)
A: To forward/reverse lever
B: To turn signal switch

30. Disassembly and Reassembly
Console Box
3-4
ELECTRICAL SYSTEM
208774
Disassembly
1. Disconnect the electrical wires at connectors 1.
(Disconnect the choke cable on the engine side.)
2. Remove four screws 2 securing the cover.
3. Remove six screws 3 and separate the front and
rear panels.
4. Remove four screws 4 securing the instrument
panel.
Reassembly
To reassemble the console box, follow the reverse of
disassembly procedure.
NOTE
To replace the instrument panel bulbs, remove
screws 3 and 4.

31. Console Box
3-5
ELECTRICAL SYSTEM
208789
Disassembly
1. Remove two screws 1 securing the cover. (Use a
flat-tip screwdriver)
2. Remove six screws 2 and separate the front and
rear panels.
3. Remove four screws 3 securing the instrument
panel.
Reassembly
To reassemble the console box, follow the reverse of
disassembly sequence.
NOTE
To replace the instrument panel bulbs, remove
screws 2 and 3.

32. Components in Console Box
3-6
ELECTRICAL SYSTEM
1
2
3
4
5
9
6
7
8
208556
1 Power relay
2 Power relay (diesel-engine models)
3 Turn signal relay
4 Glow plug relay (diesel-engine models)
5 Glow plug timer (diesel-engine models)
6 Lighting switch
7 Starter switch
8 Fuses
9 Travel speed select switch

33. Combination Meter
Disassembly
3-7
ELECTRICAL SYSTEM
5
6
7
8
9
2
1
3
4
206480
Sequence
1 Instrument panel
2 Dial
3 Engine coolant temperature gauge
4 Service hourmeter
5 Fuel gauge (diesel-engine models)
6 Meter case
7 Printed circuit plate
8 Bulb
9 Socket
CAUTION
Be careful not to damage the printed circuit
plate when disassembling the combination
meter.
Reassembly
To reassemble the combination meter, follow the
reverse of disassembly sequence.
Bulb replacement
For bulb replacement, remove the socket from the
printed circuit plate by turning it to the left. For
configuration of the indicator lights, refer to the
preceding section “OK Monitor”.

34. Major Electrical Components
Starter Switch (with Anti-Restart Lock)
3-8
ELECTRICAL SYSTEM
(OFF)
(ON)
(START)
B2
B1
M
G1
G2
S
203561A
Terminal B1, B2 G1 G2 M S
Fuse box,
Component
battery, Fuse box
Key
alternator
position
(OFF)
(ON)
(START)
Connection chart
LPG-engine models (12 V)
Terminal B1, B2 G1 G2 M S
Fuse box,
Component glow plug relay,
Fuse box Glow plug timer
Key battery,
position alternator
(OFF)
(ON)
(START)
Diesel-engine models (24 V)
NOTE
The starter switches for both LPG and diesel engines are same in design. With a LPG engine, therefore, turning
the key to a position on the left of the OFF position is possible but does not cause any effect as there is no
electric circuit connected there.
This switch has a built-in anti-restart lock, so the key
cannot be turned from (ON) to (START) position
while the engine is running. The LPG- and diesel-
engine models use the same starter switch. In the
diesel-engine models, (ON) position of the switch is
for energizing the glow plugs.

35. Lighting Switch
Turn Signal Switch
3-9
ELECTRICAL SYSTEM
8
(0.3)
8
(0.3)
OFF 1st 2nd
Stroke
[Unit: mm (in.)]
Knob position
206481
Terminal B T H P
Component Battery
Tail lamps,
Head lamps Clearance lamps
Knob (fuse)
instrument panel
position
lamp
(OFF)
1st position
2nd position
Connection chart
L
N
R
RF LF
F
203573
Terminal F RF LF
Lever Component Turn signal Turn signal Turn signal
position relay (L) (RH) (LH)
R (Right)
N (Straight)
L (Left)
Cord color Green Yellow Black
Connection chart
If the insulation resistance between any two terminals is not up to the specification indicated below when the knob is
in the OFF position, the lighting switch must be replaced with a new one.
Insulation 1 M ohm or higher
resistance (as measured by a 500 V megger)
If the insulation resistance between any two terminals is not up to the specification indicated below when the lever is
in the N position, the turn signal switch must be replaced with a new one.
Insulation 1 M ohm or higher
resistance (as measured by a 500 V megger)

36. Fuel Tank Unit
3-10
ELECTRICAL SYSTEM
To ground
To fuel gauge
212.4mm
(8.36in.)
141.4mm
(5.57in.)
E
F
3/4
1/2
1/4
203574
Terminal
E 1/4 1/2 3/4 F
Item
Standard resistance (ohm) 80 49.5 32 19 10
Tolerance (ohm) − ± 3 −
+ 1.0
− 0.5
+ 12
+ 2
Indication accuracy

37. Fuse Box
Spare Terminals
The spare terminal cord extends from the fuse box in the
console box. (Another spare terminal is located on the
chassis-side main harness.)
Removing the console box rear panel will expose this spare
terminal which is fastened to the harness protector with
vinyl tape.
3-11
ELECTRICAL SYSTEM
103240
Spare terminal
207209
Cord color Lg (light green)
Code
Gasoline-engine models Diesel-engine models
Capacity Circuit Capacity Circuit
10 A Directon lever, 10 A Directon lever,
delay timer delay timer
15 A Instrument panel, 10 A Instrument panel,
stop lamp switch, turn signal lamps
T/M controller
15 A Spare power 10 A Spare power
source source
15 A Head, working 15 A Head, working
(opt) lamps (opt) lamps
15 A Spare fuse 10 A Horn
10 A Spare fuse 10 A Spare fuse
10 A Horn 10 A Stop lamps
15 A Spare fuse 10 A Backup lamps
10 A Spare fuse 15 A Spare fuse
A
B
C
D
E
F
G
H
J
MC Model
Code
Gasoline-engine models Diesel-engine models
Capacity Circuit Capacity Circuit
10 A Directon lever, 10 A Directon lever,
delay timer delay timer
15 A Instrument panel, 15 A Instrument panel,
stop lamp switch, stop lamp switch,
T/M controller T/M controller
15 A Spare power 15 A Spare power
source source
15 A Auto light switch, 15 A Auto light switch,
working (opt) working (opt)
lamps lamps
15 A Head lamps 15 A Head lamps
10 A FC controller 10 A FC controller
10 A Horn 10 A Horn
15 A Spare fuse 15 A Backup lamps
10 A Emergency 10 A Emergency
switch switch
A
B
C
D
E
F
G
H
J
FC Model
A
B
C
D
E
F
G
H
J

38. Lamp Bulb Specifications
3-12
ELECTRICAL SYSTEM
Item No. of
Color of lens
Watts
Shape Remarks
Type of lamp bulbs 12 volt 24 volt
Head lamps 2 Colorless 45 60
Turn
2 Amber 27 25
Combination
signals
Standard:
Installed on
lamps (front)
Clearance
overhead guard
2 Amber 10 12
lamps
Turn
2 Amber 27 25
Combination
signals
lamps (rear)
Tail/stop
2 Red 8/23 10/25
lamps
Backup
2 Colorless 10 12
lamps
Working lamps
2 Colorless 45 60 Option
(front and rear)
OK monitor indicator lamps
8(Diesel)
3
or Colorless 3
and instrument panel lamp
7 (LPG)
(14 volt)
200016A

39. Battery Maintenance
1. State of charge and electrolyte specific gravity (S.G.) adjustment
3-13
ELECTRICAL SYSTEM
Specific gravity reading
State of charge Adjustment
at 20°C (68°F)
1.280 to 1.265 Fully charged If difference in S.G. between any two cells is 0.040 or more,
effect a high current discharge to minimize the difference
and then recharge battery. Adjust S.G. during recharging.
1.260 to 1.225 One-half charged Recharge battery and adjust electrolyte S.G. Make sure there
is neither faulty components, loosely connected cord nor
corroded connection.
1.220 or below Discharged Recharge battery. If difference in S.G. is large, adjust it
during recharging.
If difference in S.G. is A cell with a low S.G. During recharging, adjust S.G. to 1.280 to 1.265.
more than 0.040 is in shorted condition. If difference in S.G. is more than 0.040 and a low S.G. is
Recharge until voltage found in certain cells only, replace battery. After leaving
and S.G. stabilize and battery for 12 to 96 hours, conduct a high current discharge
have remained constant test.
for more than 2 hours.
2. Specific gravity reading and state of charge
To check the battery for state of charge, take
hydrometer readings on its electrolyte. The battery
may be fully charged if the S.G. reading is 1.280 to
1.265 at 20°C (68°F). The state of charge can be told
from the way the electrolyte level goes down to expose
the cell plates. If addition of distilled water is
necessary every month or so, the battery is
overcharged. If addition is not required for more than 3
months, it is likely that the battery is inadequately
charged.
3. Charging precautions
(1) In slow charging, the charging current should be
about 1/10 the capacity of the battery to be
charged.
(2) In quick charging, the battery capacity in ampere
should not be exceeded.
(3) During charging, adjust the charging current to
prevent the electrolyte temperature from rising
beyond 45°C (113°F).
(4) When connecting the cables to the battery, begin
with the cable for the positive (+) terminal. When
disconnecting them from the battery, begin with the
cable for the negative (−) terminal.
CAUTION
Be sure to turn OFF the starter switch and
lighting switch before disconnecting or
connecting the battery cables to prevent the
IC regulator from suffering damage.

40. Precautions for servicing charging system (with
alternator)
The alternator is equipped with a built-in IC (integrated
circuit) voltage regulator. When servicing the charging
system, pay attention to the following precautions:
(1) Do not reverse the polarity of the battery.
(2) Do not disconnect the battery terminal while the engine
is running.
(3) Do not ground the terminal L.
(4) Do not short the terminals L and R.
(5) Do not direct a blast of steam cleaner to the alternator.
Remember, a blast of steam will damage the IC
regulator.
3-14
ELECTRICAL SYSTEM
Terminal B
Terminal R
Terminal L
202772

41. FC (Finger-Tip-Control System)
Nomenclature
3-15
ELECTRICAL SYSTEM
5
6
7
8
9
4
3
1
2
103237
1 Light sensor
2 Auto-light switch
3 Flow regulator valve
4 Solenoid control valve
5 Seat switch
6 Lowering speed selector switch
7 Safety switch
8 Joystick levers (finger-tip-control system)
9 Controller

42. Maintenance Precautions
The FC model contains a microcomputer. Following are the
precautions to be observed in performing any maintenance
on the FC model.
(1) When removing the controller cover, make proper
provisions to keep out rain, washing water splashes and
the like.
(2) After using the controller setting switch, check to make
sure the control system is in keeping with the truck
specifications.
(3) Before performing repairs which require welding, be
sure to disconnect the cable from the battery positive
(+) terminal and the controller from the system at its
connectors.
(4) When handling the controller by hand, never touch its
electrical terminals, or your body charge will rupture
some of the electronic elements in the internal
controller circuits.
3-16
ELECTRICAL SYSTEM
NOTE
Improper setting of the system will result in inability to
lower the forks in an inching manner. (See “How to Set
Controller”.)
208775
208776

43. Description
1. Finger-tip-control system
This system, unlike the conventional mechanical control, is
electronically actuated to help reduce the effort required of
the operator in moving the control levers for lift, tilt and
attachment functions.
[Features]
(1) The lowering speed selector switch insures smooth fork
and mast movement no matter how abruptly the
operator may move the control levers. This switch is
ideal for handling of fragile loads.
ON: 350 mm/s (69 fpm)
OFF: 500 mm/s (98 fpm)
(2) This system provides the following safety functions:
3-17
ELECTRICAL SYSTEM
101466B
204992B
(a) The lift, tilt and attachment functions are not
performed even if the control levers are moved
when the engine is not running.
(b) The lift, tilt and attachment functions are not
performed even if the control levers are moved
when the safety switch is in ON (pushed) position.
(c) The lift, tilt and attachment functions are not
performed even if the control levers are moved
when the seat switch is not ON (the operator is not
seated).
(d) The system indicator light in the OK monitor
alerts the operator to problems occurring in the
electrical system and, at the same time, stops
function. (If any problem occurs in the lift system,
for example, the system becomes inoperative.)

44. 2. Auto-light system
The head lamps are under the control of switch and sensor.
With the auto-light switch ON, the head lamps turns ON
automatically as the truck is driven into a dark area. The
head lamps can be turned ON or OFF manually.
Operating Principles
1. Finger-tip-control system
(1) The system is activated by turning ON the safety switch
when the engine is running and the seat switch is ON
(when the operator is seated).
(2) As the control levers (joysticks) are moved to operate
the equipment (mast and forks), the amount of lever
movement will be translated into an electrical signal:
this signal goes into the controller, in which it is
converted to and output signal. At this point the
controller issues and ON signal to the unload solenoid,
thereby turning ON this solenoid to introduce hydraulic
pressure into the control valve. The system is now
ready to actuate the equipment. The output signal
applies to the proportioning solenoid selected by the
direction of the joystick movement. Inside the control
valve of that solenoid, its spool is forced to slide,
altering the internal oil passage to direct the oil to the
corresponding cylinders. The spool keeps on sliding
until it comes to the position at which the pressure of its
pilot chamber becomes equal to the force of its
centering spring. In the meantime, the cylinder extends
or retracts against its load. As the joystick is moved
back to its neutral position, the signal to the
proportioning solenoid dies to lower the pilot chamber
pressure and allow the centering spring to push the
spool to its neutral position, whereby the line to the
cylinder becomes shut off: the pressure in the line is
now trapped, holding the cylinder there. At the same
time, the ON signal to the unload solenoid goes OFF, so
that the part of the system actuating the equipment goes
into no-load state.
3-18
ELECTRICAL SYSTEM
101489

45. (3) Power supply to the controller is initiated from the
starter switch through a 10-Amp fuse and safety switch.
Pressing this switch into OFF position shuts down the
controller without shutting down the engine.
(4) With the starter switch and safety switch turned ON, the
unloading solenoid and proportioning solenoid are
under control of the joysticks. With the engine shut
down (and hence the hydraulic pump standing still), the
spools in the control valves are inoperative because no
pressure develops in their pilot chambers.
Consequently, the equipment remains inoperative even
when the starter switch and safety switch are turned
ON.
3-19
ELECTRICAL SYSTEM

46. 3-20
ELECTRICAL SYSTEM
Consolebox
Control(joystick)box
Control
lever
(joystick)
Lowering
speedselector
switch
Safety
switch(ON)
Safetyswitch(OFF)
Seatswitch
(ON)
System
indicator
light
Starter
switch
(ON)
Fuse
10A
Liftcylinder
Unload
solenoid
Proportioning
solenoid
Solenoid
control
valve
Hydraulic
pump
Proportioning
solenoid
Pilotpressure
passage
Centeringspring
Pilotpressure
passage
Detailofcontrolvalve
Powersupply
Powersupply
Flowcontrolsignal
Powersupply
Spool
Setting
window
Controller
Battery
ON-OFFsignal
ON-OFFsignal
ON-OFFsignal
Leverstrokesignal
208777
Finger-tip-controlsystemschematic

47. (5) In addition to the functions explained above, the
controller monitors the supply voltage and the electrical
connections for the control levers (joysticks), solenoids
and other input/output devices, and alerts the operator
to a problem, if occurs, by flickering the system
indicator light and turning ON this light and also LED
(as shown in the chart below). Such a problem is
usually a fault in the harness or connector and must be
located by inspecting. The hydraulic components such
as pump control valve, etc. are not monitored.
3-21
ELECTRICAL SYSTEM
208778
System
LED flickering pattern Problem detected Effect indicator
light
(Normal) OFF
Open- or short-circuit in control
lever (with starter switch in ON
No power supply to
ON
position)
particular system
Supply voltage too high (over No power supply
32 volts or too low under 9 volts) to all systems
ON
Open- or short-circuit in No power supply to
solenoid particular system
Control lever neutral position No power supply to
displaced particular system
Flickers
Open- or short-circuit in control
lever (with starter switch in ON
position)
Seat switch OFF, of open-circuit No power supply to
Flickers
in it all systems
LED remains ON Problem in controller
NOTE: Any problem does not cause the engine to shut down.
LEDflickersLEDflickersLEDflickersLEDflickersLEDflickers
204995A
1.2 sec. 1.2 1.2 1.2
0.3 2.1 0.3 2.1
0.6 0.6
1.2 0.6 0.6 0.6 0.6 1.2
1.2 0.3 0.3 0.3
0.6 0.6 0.6
0.9

48. 3-22
ELECTRICAL SYSTEM
2. Auto-light system
(1) The auto-light system turns ON the head lamps
automatically when the truck is driven into a dark
area, with the starter switch in (ON) position, the
safety switch ON and the auto-light switch ON.
The controller is common to this system and the
finger-tip-control system but the circuit of the
system is independent so the components of these
systems do not affect each other in operation.
Example: The auto-light system functions regardless
of ON-OFF of the seat switch. The finger-
tip-control system functions even if the
light sensor is faulty.
208781
Light sensor
Auto-light switch Power relay
Major Components of Auto-light System
208779 208780
102454
NOTE
The controller has no auto-light system diagnosing
function.

49. (2) The light sensor is basically a resistance device, whose
resistance is compared with that in the variable resistor
(the auto-light sensitivity adjusting knob) inside the
controller. The sensor resistance increases as brightness
decreases. When, in operation, the sensor resistance
becomes greater than the resistance in the variable
resistor, the comparing circuit energizes the power relay
to close its contacts to turn ON the head lamps.
3-23
ELECTRICAL SYSTEM
Control (joystick) box
Safety switch
(ON)
Power supply
Controller
(ON)
Setting
window
Auto-light sensitivity
adjusting knob
Battery
10 A
20 A
Head lamp
Tail lamp
Console box
Instrument panel lamp
Clearance
lamp
Dark
Light
sensor
Power relay
(ON)
Starter switch
(ON)
Auto-light
switch (ON)
B P H T Lighting
switch
Operation–1
With auto-light switch ON, starter switch
(ON) and safety switch ON
208782

50. (3) With the auto-light switch turned OFF, the lighting
switch can be used to turn ON a light selected by the
position of this switch. Even under this condition, the
power relay goes ON or OFF in response to changes in
ambient brightness but this does not affect the light
turned ON by the lighting switch. With the auto-light
switch OFF, the starter switch (ON) and the safety
switch ON.
3-24
ELECTRICAL SYSTEM
Control (joystick) box
Safety switch
(ON)
Power supply
Controller
(ON)
Setting
window
Battery
Power relay
(ON)
10 A
20 A
Head lamp
Tail lamp
Console box
Instrument panel lamp
Clearance
lamp
Dark
Light
sensor
Starter switch
(ON)
Auto-light
switch (OFF)
B P H T Lighting
switch
Operation–2
With auto-light switch OFF, starter switch
(ON) and safety switch ON
208783

51. (4) Turning OFF the safety switch with the auto-light
switch ON causes the power relay to remain OFF.
Under this condition, all lamps will not come ON. If the
auto-light switch is OFF, the lighting switch is effective
and can turn ON each selected light, regardless of the
safety switch and starter switch.
Operation logic:
Auto-light switch OFF
Auto-light switch ON
Dark Bright
Lighting switch OFF
1st 2nd
OFF
1st 2nd
OFF
1st 2nd
position position position position position position
Clearance, tail lamps
Head lamps
3-25
ELECTRICAL SYSTEM
Control (joystick) box
Safety switch
(OFF)
Power supply
Controller
(OFF)
Setting
window
Battery
Power
relay
10 A
20 A
Head lamp
Tail lamp
Console box
Clearance
lamp
Dark
Light
sensor
Starter
switch
Auto-light
switch (ON)
B P H T Lighting
switch
Operation–3
With auto-light switch ON and safety switch ON
208784

52. How to Set Controller
Set the controller on any of the following occasions:
Occasion Setting
After mast has been changed, or an optional Resetting of setting switches
equipment added
When auto-light system is adjusted Adjustment of brightness at which light sensor operates
After control valve lift section solenoid has Adjustment of maximum lowering speed (when required)
been replaced (or control valve replaced)
After controller assembly has been replaced • Resetting of setting switches
• Adjustment of maximum lowering speed (when required)
• Adjustment of brightness at which light sensor operates
(when required)
3-26
ELECTRICAL SYSTEM
208785

53. 1. Setting switches
The controller has a total of 16 setting switches.
(1) Switch setting pattern (Black dot indicates switch
head.)
(2) Example of setting
Truck: GP40K
No. of spools: 3V
Mast: 4V40A (simplex)
Option: Speedometer with indicator light
3-27
ELECTRICAL SYSTEM
NOTE
Use a screwdriver to move each switch. The switch is
made of resin; be careful not to damage the switch
head in setting.
SW3
ONOFF
SW2
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
Setting window
OFF
OFFMode Normal Check
OFFSwitch SW 2–1 ON
Transmission speed 1200 bps 9600 bps
OFFSwitch SW 2–2 ON
Spear Normal –
OFFSwitch SW 2–3 ON
Seat switch With Without
OFFSwitch SW 2–4 ON
Oil pressure sensor Without (With)
OFFSwitch SW 2–5 ON
Spear Normal –
OFFSwitch SW 2–6 ON
WDT operation Normal mode WDT disabled
OFFSwitch SW 2–7 ON
Spear Normal –
OFFSwitch SW 3–7 ON
Mast model Standard
OFF
Simplex
OFF
Duplex
OFF
Triplex
OFFSwitch SW 3–5
OFF OFF OFF OFFSW 3–6
No. of spools 2 V
OFF
3 V
ON
4 V
OFF
–
ONSwitch SW 3–3
OFF OFF ON ONSW 3–4
Truck model 40K
OFF
40KL
OFF
45K
OFF
50K
OFFSwitch SW 3–1
OFF OFF OFF OFFSW 3–2
Program mode User program Boot mode
OFFSwitch SW 2–8 ON
Spear Normal –
OFFSwitch SW 3–8 ON
208786
205001
40 K
3 V
Standard
SW3SW2
Seat switch
208787

54. 2. Failures resulting from incorrect setting
(1) Incorrect setting for truck size (4.0 ton, 4.5 ton and 5.0
ton models)
Incorrect setting will result in abnormal lowering speed
and inching feel. If a setting for a 4.0 ton model is made
on a 4.0 ton mode, for example, the lowering speed will
be abnormally low. If a setting for a 4.5 ton model is
made on a 5.0 ton model, the lowering speed will be
abnormally high.
(2) Incorrect setting for number of control valve spools
(a) If the setting is made for the number of spools
greater than is actual, the system indicator light
will flicker, and the equipment will not be
actuated. (Such a setting is taken as open- or short
circuit in the control valve solenoid or in the
joysticks.)
(b) If the setting is made for the number of spools less
than is actual, only the devices equal to the number
of the set spools will be actuates.
(3) Incorrect setting for mast
A setting for a simplex mast will not affect the lowering
speed.
(4) Incorrect setting for controller check (Be sure to set to
OFF.)
If it is set to ON, the equipment will not be actuated
even if the joysticks are operated.
3. Lowering speed adjusting knob
(1) This knob is for increasing or decreasing the maximum
lowering speed.
(2) The arrow of the knob has been set to “8”.
(3) The lower the figure, the more the lowering speed is
decreased. “A” thru “F” mean “10” thru “15”.
3-28
ELECTRICAL SYSTEM
NOTE
(1) Use a screwdriver to turn the knob.
(2) This knob can be turned endlessly in both
directions.
(3) Be careful not to damage the groove of the knob
when putting a screwdriver.
205004

55. 4. Auto-light sensitivity adjusting knob
(1) This knob is for adjusting the sensitivity level at which
the auto-light system turns ON and OFF the head
lamps.
(2) The knob has been set as shown.
(3) The more the knob is turned to the right, the lower will
be the sensitivity at which the system turns ON and
OFF the head lamps.
5. Working precautions
(1) When installing the controller, position it correctly. Be
careful not to turn upside down.
(2) When resetting or adjusting the controller on the truck,
be sure to turn OFF the starter switch and lighting
switch.
(3) When removing the rubber cover, check to see if the
sealing label was removed before. (If this label shows a
sign of removal, ask the user for removal of the label.)
(4) Be careful not to damage the rubber cover when it is off
the controller.
(5) Do not let any foreign matter fall into the controller
through setting window.
3-29
ELECTRICAL SYSTEM
205005
205037
NOTE
(1) Use a screwdriver to turn the knob.
(2) Be careful not to damage the groove of the knob
when putting a screwdriver.

56. 3-30
ELECTRICAL SYSTEM
Troubleshooting
Starter System
Weak or dead battery Recharge or replace.
Short or open circuit Repair or replace.
Poor continuity in starter switch Replace.
Starter or starter relay defective Replace.
Forward-reverse lever not in neutral Move lever to neutral
position position.
Open or short circuit Repair or replace.
Engine stop solenoid defective Replace or readjust.
Control timer defective Replace.
Gauges
Open or short circuit Repair or replace.
Gauge internally defective Replace.
Gauge unit defective Replace.
Gauge or gauge unit not of the type Replace.
called for
Loose terminal connection Repair.
Circuit between gauge and gauge unit Repair.
grounded
Gauge internally defective Replace.
Open or short circuit Repair or replace.
Gauge internally defective Replace.
Gauge unit defective Replace.
Gauge or gauge unit not of the type Replace.
called for
Loose terminal connection Retighten.
Circuit between gauge and gauge unit Repair.
open or short
Gauge internally defective Replace.
Gauge unit defective Replace.
Circuit between gauge and gauge unit Repair.
grounded
Gauge unit defective Replace.
Gauge internally defective Replace.
Starter will not crank
engine
Starter switch
Temperature
gauges
Fuel gauge
Turning off starter
switch will not stop
engine
Will not indicate at
all
Will not indicate
accurately
Will indicate higher
than actual
temperature
Will not indicate at
all
Will not indicate
accurately
Will indicate “full”
regardless of amount
of fuel left in tank
Will indicate
“empty” regardless
of amount of fuel
left in tank

57. 3-31
ELECTRICAL SYSTEM
Lighting System
Weak or dead battery Recharge or replace.
Fuses blown out Check and replace.
Open or short circuit Repair or replace.
Poor grounding Clean ground spot and
re-make connection.
Bulbs burnt out Replace.
Weak or dead battery Check and recharge.
Burned contact points in switches Repair or replace.
Loose terminals Retighten.
Dirty lenses Clean.
Waterdrops inside lenses Dry and replace packings.
Bulbs expired in service life Replace.
Lighting switch defective Replace.
Bulbs burnt out Replace.
Turn signal switch defective Replace.
Turn signal relay defective Replace.
Turn signal relay defective Replace.
Bulbs burnt out Replace.
Wrong wattage of bulbs Replace.
Bulbs burnt out Replace.
Turn signal relay defective Replace.
Wrong wattage of bulbs Replace.
Turn signal relay defective Replace.
Backup lamp switch defective Correct if improperly
installed: replace if
internally defective.
Bulbs burnt out Replace.
Alarm Unit
Fuse blown out Check and replace.
Open or short circuit Repair or replace.
Horn switch defective Replace.
Horn defective Replace.
Horn button defective Repair or replace.
Horn switch defective Replace.
Horn defective Replace.
Will not light
Will not light
Lamps - general
Head lamps
Will light dimly
Turn signals
Other lamps
Horn
Will not flicker
Will not go out
Will flicker too
slow
Will flicker too
fast
Backup lamps
will not light
Will not give
blast of sound
Will give ugly
blast of sound

58. 3-32
ELECTRICAL SYSTEM
Battery
Drive belt slipping Readjust.
❋ Alternator
Stator coil grounded or open-circuited Repair or replace.
Rotor coil open Replace.
Brushes poorly seating on slip rings Replace brushes if worn.
Clean holder and polish
slip rings.
Diode ruptured Replace.
❋ Regulator
Regulated voltage setting too low Readjust.
❋ Battery
Not enough electrolyte or wrong proportion of acid to Refill and check specific
water gravity.
Battery cell plates deteriorated (forming, possibly Replace.
internal short-circuit)
Terminal connections loose Clean and retighten.
❋ Wiring
Open or loose connection between starter switch and Repair.
regulator IC terminal
Fuse blown, or loosely set in holder Replace and repair.
Open or loose connection between F terminals of Repair.
regulator and alternator
❋ Wiring
Regulator IC and F terminals shorted or miswired Repair.
Poor grounding of regulator F terminal Repair.
❋ Regulator
Pressure coil open-circuited Replace.
Regulated voltage too high Readjust.
Tends to run down
rapidly
Tends to get
overcharged

59. FC (Finger-Tip-Control System)
1. Preparatory steps
(1) This system comes into operation when the starter
switch is turned to the ON position and the safety
switch is turned ON. The finger-tip-control comes into
operation after the seat switch has been closed (the
operator has been seated) and the engine has been
started.
(2) Before deciding to replace a blown fuse, check to be
sure that the harness connectors in the power line are all
in sound condition, free of any sign of short-circuit.
(3) The use of the test-use connector (special tool) is
prescribed for checking the connector-to-connector
(special tool) is prescribed for checking the connector-
to-connector lines for continuity and for reading the
voltage across two terminals and the ohmic resistance
of a line.
(4) The controller’s capabilities include that of self-
diagnosis (for the control system only) function. By this
function, any trouble symptom occurring in energized
state goes into memory as trouble data. (This memory
capability is limited, however, to the latest single case
of trouble symptom for one input/output channel:
previous symptoms are not memorized, meaning that
their chronological order and data are not traceable).
The trouble symptom data, limited as above, can be
read out through the ground support equipment (GSE).
If, however, any of the following steps is taken, the
stored data will be erased and lost:
3-33
ELECTRICAL SYSTEM
205038
(a) Disconnecting battery lead from the battery
terminal, positive (+) or negative (–).
(b) Uncoupling CN1 or CN4 connector on the console
box.
(c) Removing the 10-A fuse (6th fuse as counted from
top) in the fuse box.
(d) Uncoupling CN53 connector on the controller.
(e) Turning starter switch or safety switch ON and
OFF twice in succession. (Turning the switch in
this manner is the same thing as performing the
cycle of energizing and de-energizing the
controller twice in succession.)

60. Conditions in
Check item What to check Remedy
the machine
Starter switch OFF Hydraulic line Hoses, pipes and connectors for damage Repair leaking or
Safety switch OFF and sign of leak. damaged parts.
Hydraulic devices Check control valve and hydraulic Repair damaged or
cylinders for damage and oil leaks. leaking parts, if any.
Electrical connectors Check connectors for tightness, burns and Repair.
and wires breakage; check wires for insulator
stripping and signs of rubbing.
Power source voltage Check to be sure that voltage is at least Correct alternator or
10 V as read across battery’s terminals. battery if this voltage
is too low.
Engine at standstill System check lamp Check to be sure the lamp goes ON and Replace lamp bulb if
Starter switch ON OFF properly; if not, check its bulb. blown.
Safety switch ON
Auto-light unit After making sure check light bulb is OK, Refer to Case 1 and 2.
see if auto-light works properly.
LED indicator (red) Be sure that red LED go ON and OFF Proper functioning of
in the controller correctly. LED indicator is essential
to troubleshooting.
Trouble-data reading Connect GSE to controller and check its (Proper functioning of
function of controller input and output actions. controller is essential to
troubleshooting.)
Engine running Hydraulic devices With your hands kept off control levers, Refer to the sections
Safety switch ON see if solenoid valves and hydraulic pump dealing with control
are making any abnormal sound. valve and hydraulic
pump,
respectively.
Operate control lever to see if any abnormal (Proper function of
sound, indicative of flow throttling, comes solenoid valves is
from control solenoid valve or from any essential to
other solenoid valve. troubleshooting.)
Check to see if unload solenoid valve
operates properly, in response to a lever
being moved.
Work attachments Check each work attachment for the
following:
(a) Does it work properly? Refer to Case 3.
(b) Does it “inch” properly? Refer to Case 4.
(c) Does mast go down with proper
speed? Refer to Case 5.
3-34
ELECTRICAL SYSTEM
(5) When coupling or uncoupling a connector, make
sure that the starter switch is OFF. Never try to
insert or pull off the connector half forcibly or its
pins will suffer damage. When coupling a
connector, be sure that the inserted half snaps into
its self-locking position.
(6) Before starting troubleshooting work, check to be
sure that the following conditions are met on the
machine side:

61. 2. Connecting the GSE to the Controller
(1) Remove the rubber cap.
(2) First, turn ON the starter switch. After this, select the
lift menu (by referring to the GSE operation manual).
3-35
ELECTRICAL SYSTEM
208788
NOTE
Before plugging in or unplugging the GSE cable, be
sure to have the starter switch turned OFF.

62. 3-36
ELECTRICAL SYSTEM
3. Troubleshooting Cases as Examples
(1) Explanatory notes and reminders
(a) In the text and diagrams to follow, electrical
connectors are abbreviated CN. An individual
CN will be identified by a number suffix (used
in the electrical wiring and connecting
diagrams).
(b) In the flowchart diagrams, the numerical
notation in the box, , is a circuit number.
The terminals of a connector too will be
identified by circuit numbers. As to the
configuration of terminals in each connector,
refer to the wiring diagram.
(c) The wiring diagrams show the connector’s
terminal configuration on its male side:
remember, the configuration on the female side
is a mirror image of the male-side
configuration.
(d) In the trouble cases cited hereunder, “check the
connector coupling” means “uncouple and then
couple the connector, inserting the connector,
inserting the connector half all the way to self-
locking position.”
(e) In the trouble cases cited, “continuity check”
will be directed for some harnesses. This
direction applies also to “check the connector
coupling”: when checking a connector as in
(d), above, be sure to check the connector for
circuit continuity immediately after coupling it.
(f) When reading a voltage with a circuit tester, be
sure to discriminate polarities, (+) and (–), so
that the tester will not suffer internal damage.
(g) Trouble data stored in the controller, as
explained in 1. (4), can be read out by the GSE.
Such a read-out is the “data on trouble as was”
and must not be interpreted as data on the
trouble confirmed to exist. To illustrate this
point, assume that the data are currently
displayed in the form shown on the right and
that the indicated faulty conditions have
already been corrected by repair. In this case,
the work attachment in question remains
inoperative. Thus, it is important that, each
time a detected malcondition is corrected and
eliminated, the trouble data be changed
promptly to reflect the correction effected.
NOTE
For the method of deleting the data stored in the
controller, refer to (a) thru (e), 1. (4).
Component Trouble symptom
Control levers Short-circuit
Solenoid valves Short-circuit, oil leakage

63. (h) Not withstanding what is said in (g), above, the “data
on past trouble,” as read into the GSE from the
controller, can be useful information in checking for
such malconditions (like an open due to loose contact in
a circuit) as may not show up later at the time of
performing a troubleshooting work. The diagram,
below, illustrates and example of precarious type of
malcondition:
3-37
ELECTRICAL SYSTEM
The malcondition on the left, detected at the time of
trouble occurrence, will go into the data as “open-
circuit” if it happens to present an open.
Supposing that, as you start the troubleshooting
work with the GSE, the near-open fault happens to
be in a precariously closed condition: then, the GSE
will indicate the circuit of the device in question as
normal whereas the data held in the controller reads
“open-circuit” for that device.
208790
Trouble symptom data Device
Past Open-circuit
Now Normal
Trouble symptom data Open-circuit

64. (2) Auto-light System Troubleshooting
3-38
ELECTRICAL SYSTEM
Control(joystick)box
Safetyswitch
Powersupply
Auto-light
sensitivity
adjustingknob
Turn-On
Setting
window
Battery
Power
relay
10A201
184ONorOFFsignal
Controller
173
177
169
182
169
177
173
184
183
186
187
20A
Lighting
switch
Headlamp
Taillamp
Consolebox
Clearance
lamp
DarkBright
Light
sensor
Starter
switch
Auto-light
switch
Instrumentpanellamp
OFFON
BPHT
208791
Auto-lightsystemschematicNOTE:CircuitNos.areindicatedbysmall-characternumbers.

65. (a) Case 1: Head lamps will not go ON in darkness.
Troubleshooting procedure
3-39
ELECTRICAL SYSTEM
Is the LED (red) ON in the
controller?
Do the head lamps go ON when
the sensitivity is re-adjusted?
Refer to Case 7:
“Controller’s LED (red) will not go ON.”
No
Yes
Set the sensitivity to make the lamps turn ON at the
desired degree of darkness.
Yes
No
Do the head lamps go ON when
circuit (CN51) is grounded
(shorted to the ground)? (Does
this shorting cause the power
relay to trip ?)
173 Check CN51, CN52 and CN53 for continuity. If
these connectors are OK, it means that the controller
is in faulty condition and needs to be replaced.
Yes
No
Have circuit shorted to
circuit at the male side of
CN4. Then, ground circuit :
will this turn ON the head lamps?
173
201
184
Check the circuits of power relay and auto-light
switch (in the console box) for continuity. As
necessary, repair or replace.
Check harness B for continuity and repair faulty part
or line, if any.
No
Yes

66. (b) Case 2: Head lamps will not go OFF when bright.
Troubleshooting procedure
3-40
ELECTRICAL SYSTEM
Is the LED (red) ON in the
controller?
Do the head lamps go OFF when
the sensitivity is re-adjusted?
Refer to Case7:
“Controller’s LED (red) will not go ON.”
No
Yes
Set the sensitivity so that the lamps will go OFF at
the desired degree of darkness.
Yes
No
Do the head lamps go OFF when
CN51 is disconnected?
Is the resistance through CN52 (between circuits
and ) less than 20 kilohms?169177
Yes
Check power relay and
auto-light switch (in the
console box) for short-
circuit, and repair or
replace.
Check the light sensor
circuit for continuity and
repair or replace.
See if circuit of
harness B is shorted to
chassis or to ground
circuit and, if so, repair.
173
No
Do the head lamps go OFF when
CN4 is disconnected?
No Yes
No
Check CN51, CN52 and
CN53. If these connectors
are OK, it means the
controller is in faulty
condition and needs to be
replaced.
Yes

67. (3) Control System Troubleshooting
3-41
ELECTRICAL SYSTEM
Consolebox
System
indicator
light
Control(joystick)box
Starter
switch
10A
Seatswitch
Control
lever
(joystick)
Loweringspeed
selectorswitch
Safty
switch
Powersupply
ONorOFFsignal
Leverpositionsignal
OnorOFFsignal
Controller
Setting
window
Flowcontrolsignal
Proportioning
solenoid
Control
valve
unit
Unload
solenoid
Hydraulic
pump
Liftcylinder
208792
Controlsystemschematic

68. (a) Case 3: No motion of hydraulic cylinders.
Troubleshooting procedure
3-42
ELECTRICAL SYSTEM
Is the system check lamp ON or OFF?
Connect the GSE to the controller and
read out the current trouble data.
Use GSE to
monitor trouble.
Are all levers normal?
Re-set.
Is the controller set to
match the machine
specification?
Is safety switch off ?
Move the control lever: does throttling
noise or any other abnormal noise come
from the control valve? (Does the
unload solenoid operate?)
Is the controller’s LED (red) ON or
OFF?
Check the harness and connectors of the lever in question for
continuity. If open-circuit condition is noted, replace the lever
assembly.
Check for continuity the harness and connectors of the
component in question. If open-circuit is noted, replace the
component.
Check for continuity the harness and connectors of the solenoid
in question. If open-circuit is noted, replace the solenoid.
(Refer to the section on solenoid control valves.)
Check for continuity the harness and connectors of the lever in
question. If short-circuit is noted, replace the lever assembly.
Check for continuity the harness and connectors of the
component in question. If short-circuit is noted, replace the
component.
Check for continuity the harness and connectors of the solenoid
in question and, if short-circuit is noted, replace the solenoid.
(Refer to the section on solenoid control valves.)
Refer to case 7.Refer to case 8.
Turn OFF
safety switch.
The control valve
is internally in
faulty condition.
OFF
Flicker
No
No
No
No
No
No
No
No
No
No
Stays ON or flickers
Yes
Are all input trouble data (on a lever), as
read by the GSE, normal?
Yes
Are all output trouble data (on the
sensor), as read, normal?
Yes
Are all output trouble data (standard), as
read, normal?
Yes
Are all output trouble data (on the work
attachment), as read, normal? (This does
not apply to the two-element control
valve unit.)
Yes
Read the past trouble data into the GSE.
Are all input trouble data (on the lever),
as read, normal?
Yes
Are all input trouble data (on the
sensor), as read, normal?
Yes
Are all output trouble data (standard), as
read, normal?
Yes
Are all output trouble data (on the
attachment), as read, normal?
To deal with an internal malcondition of
any solenoid control valve, refer to the
section on solenoid control valves. If
necessary, contact the manufacturer.
Yes
Yes
No
Stays ON Stays OFF
Yes

69. (b) Case 4 : No inching motion of hydraulic cylinders
Troubleshooting procedure
3-43
ELECTRICAL SYSTEM
Does abnormal noise issue out
when the mast is operated with
normal working speed?
Check for hitching, sticking and rattling. Repair to
smoothen the movements.
Re-set.
Yes
No
Is the controller set to match the
machine specifications?
No
Yes
The cause is a malcondition within the solenoid
control valve. If necessary, contact the manufacturer.
Connect the GSE to the controller
and read “Input condition” into
the GSE. Check to be sure that
the data, as read, indicate the
control lever 76 HEX to 8A
HEX.
No
Move the control levers slowly
back and forth and check that
indication varies continuously
between 0 and 100%.
Test the control lever, as above,
twice or thrice, to be sure there is
no jump or dip in the rising
indication.
Check the harness and connectors
of the lever in question for
continuity. If discontinuity is
noted, replace the lever assembly.
Yes

70. (c) Case 5: The maximum lowering speed of the mast is too high (or too low).
Troubleshooting procedure
3-44
ELECTRICAL SYSTEM
Is the controller set to match the
machine specifications?
Re-set.
(End)
No
Yes
Is the adjusting knob (for the
max. lowering speed of the mast)
effective in adjusting this speed
of the mast?
Yes
No
The lever is faulty or there is something wrong with
the harness.
Connect the GSE to the controller
and read out “Input condition”
into the GSE.
No
Does the indication on the output
monitor screen vary between 0
and 100% as the lever angle is
changed?
Are there changes in current of
the order of 0.4 to 0.9 A?
Yes
The solenoid valve is faulty or
there is something wrong with the
harness.
Yes
The controller is faulty or there is something wrong
with the harness.
No

71. (d) Case 6: During the lowering action of a lift cylinder differ in actuating speed.
Troubleshooting procedure
3-45
ELECTRICAL SYSTEM
Is the controller set to match the
machine specifications?
Re-set.
No
Yes
Connect the GSE to the controller
and read out “Input state (2)” into
the GSE.
No
Contact the manufacture.
Operate the mast: see if the lift
cylinder indication make an ON-
to-OFF change when 2nd
cylinder starts rising from its
fully retracted position. Will the
change occur? (Test twice or
thrice to be sure of the lift
cylinder action.)
Yes
Check for continuity the harness
and connectors of the lift cylinder
circuit. As necessary, replace the
lift cylinder.

72. (e) Case 7: Controller’s LED (red) will not go ON.
Troubleshooting procedure
3-46
ELECTRICAL SYSTEM
Check the fuse. Is the fuse OK or
NG?
Read the voltage between ground
and circuits and
(CN53). Is the reading at least 10
volts? (Is power being supplied
to the controller?)
183182
Replace the fuse, and check the harnesses for open
or short.
NG
OK
Is the voltage between circuit on the male side
of CN4 and ground at least 10 volts?
201No
Yes
Is there continuity between
circuits and and the
ground?
187186
Yes
Is there continuity between circuit (on the
female side of CN4) and circuits and (at
CN53)?
183182
201
Is there continuity between circuits and
at the male side of CN54?
201183
Check the safety switch and engine hood harness for
open-circuit. Repair and correct an open if any, or
replace the switch as necessary.
Check harness B for continuity.
Repair and correct an open, if
any.
Check to be sure that
CN51, CN52 and CN53
are all in sound
condition. If the trouble
persists, replace the
controller.
No
Yes
Yes
Check the power supply
circuit (inside the console
box) for continuity.
Repair and correct an
open if any.
No
Yes
While making sure that
each connector is coupled
up tight, check to see if
the LED turns ON; if not,
contact the manufacturer.
No
No

73. (f) Case 8: Controller’s LED (red) will remain ON.
Troubleshooting procedure
3-47
ELECTRICAL SYSTEM
Does the LED remain OFF,
indicating the power supply is
faulty?
Is the voltage between circuit on the male side
of CN4 and ground at least 10 volts?
201No
No
Yes
Is the resistance between circuit (on the female
side of CN4) and circuits and (at CN53)
less than 0.1 ohm?
183182
201
If the resistance between circuits and on
the male side of CN54 less than 0.05 ohm?
201183
Check the safety switch and engine hood harness for
open-circuit. Repair and correct an open if any, or
replace the switch as necessary.
Re-set.
Check harness B for continuity.
Repair and correct an open, if
any.
If the LED remains ON;
Are the DIP switches correctly
set?
Is the SW2-8 set OFF?
Replace the controller.
Yes
Yes
Check the power supply
circuit (inside the console
box) for continuity.
Repair and correct an
open if any.
No
Yes
While making sure that
each connector is coupled
up tight, check to see if
the LED turns ON; if not,
contact the manufacturer.
No
No

74. 4. How to Move the Mast in an Emergency
If the truck fails while at work and, you then have to drive it
(if the engine is OK) or tow it to some distant place or to
the repair shop, do the following steps:
(1) Mast lowering
(a) Loosen lock nut 1 on the lift section of the contrl
valve.
(b) Using an Allen wrench, slowly loosen screw 2.
This causes the mast to go down by gravity: tighten
screw 2 and the mast will stop.
(c) Tighten lock nut 1.
(2) Lifting, tilting or auxiliary function
3-48
ELECTRICAL SYSTEM
205008
CAUTION
Before doing these steps, be sure that there is
no one standing under the mast.
CAUTION
Leaving nut 1 loose is dangeraous: the mast
might suddenly start going down by itself.
CAUTION
Steps (a) thru (i), below, are dangerous for the
following actions:
Action Remarks
Lowering the mast
Mast will move in free-falling
manner.
Dumping the hinged
fork (or bucket) Jerky dumping action.
Dumping the dump (The load will fall off.)
fork (or bucket)
Releasing clamped
The load will fall.
load

75. (a) Remove the unload solenoid connector of the
control valve. Remove the proportional solenoid
connector on that end of the control valve which is
for the action you need.
(b) Using a circuit tester, check the two solenoids
(unload solenoid and proportional solenoid) for
short or open. The faulted solenoid, if any, must be
replaced by a new one at this time. (If the
proportional solenoid, from which you pulled off
the connector half, is faulty, you may replace it
temporarily by another solenoid in place on the
control valve.)
(c) To the two connector halves, from which the female
halves were disconnected in step (a), above, couple
the female halves of the emergency-use harness
(special tool), as shown.
Special tool needed
(d) Connect the “black” alligator clip (of the other end
of the harness) to the negative (–) terminal of the
battery: have the other (red) alligator clip put on the
harness, as shown.
(e) Start up the engine.
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ELECTRICAL SYSTEM
Attachment 2Mast down
Unload solenoid
connector
Operates when
lever is pushed.
Attachemnt 2Mast up
Tilt forward Attachment 1
Tilt backward Attachment 1
Operates when
lever is pushed.
Proportioning solenoid connectors
Proportioning solenoid connectors
From
bottom
to top
208793
205010
Emergency-use harness 91105 - 00400

76. (f) Hold the engine in idling condition. Look around
the machine to be sure no one stands near the truck.
Now, take off the “red” alligator clip and touch the
battery’s positive (+) terminal with it: as you do so,
the action you need (corresponding to that of the
proportional solenoid now connected to the battery)
will start: the action will stop as you remove the
“red” clip from the terminal.
(g) If the desired action does not occur in step (f),
above, it means that there is some malcondition
inside the control valve.
(h) Stop the engine, and remove the emergency-use
harness.
(i) Re-couple the connectors of unload solenoid and
proportioning solenoid.
3-50
ELECTRICAL SYSTEM
CAUTION
(1) Do not keep touching the battery terminal (+)
with the “red” alligator clip, or the solenoid
will get burned. Touch intermittently.
(2) You may raise the engine speed while
intermittently energizing the solenoid but do
so cautiously, keeping an eye on the action in
progress.
205011

77. (3) How to cope with a failed (open-circuited) seat switch
Your troubleshooting investigation might reveal that the
seat switch is open-circuited or otherwise faulted and
will not function.
In such a case, you can create a temporary circuit
continuity through the seat switch line. The method is
explained in this illustration. The seat switch is a
security part. Be sure to replace it by a new one as
soon as possible.
3-51
ELECTRICAL SYSTEM
Two connectors are in the seat switch
line at the indicated location. Open
these connectors, and couple up the
male and female connector halves to
form a circuit bypassing the seat
switch.
208794
CAUTION
Illustrated above is a first-aid method
permissible only in an emergency situation. Be
sure to restore the seat switch line to the
normal hookup after replacing the failed switch.

78. 5. How to Clean Harness Connectors and System
Components
(1) Open-circuit trouble is often due to the harness
connectors and components in dirty condition: dust,
together with greasy matter, forms grime which, in
time, penetrates electrical connections, resulting in
loose metal-to-metal contact or, for worse, electrical
separation of surfaces in contact. For this reason, it is
essential that the connectors and components be
cleaned at each periodic inspection and at the time of
servicing the machine. Instead of a commonly used
solvent, use electronic parts cleaner (in the manner
illustrated on the right).
(2) After checking the connector for continuity, wash it as
above. Then, uncouple the connector and spray contact
surface activator onto contact surfaces. Now, install
and remove the connector several times to wet the
surfaces thoroughly with the activator liquid. After
coupling up the connector so sprayed on, check to be
sure that it is in locked state.
3-52
ELECTRICAL SYSTEM
208795
205047
NOTE
The cleaner liquid is volatile. All you have to do is
just give a strong spray to wash off grime. No need to
wipe off the sprayed liquid.
NOTE
Do not spray too much: bear in mind that this spray
liquid reacts with some resins (plastic materials).
Electronic parts cleaner ThreeBond 29B
Contact surfaces activator
ThreeBond 2501S
(aerosol)

79. 6. Troubleshooting Guide for Solenoid Control Valves
7. Troubles Conceivable for Each Component
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ELECTRICAL SYSTEM
Trouble symptoms Possible causes Remedies
The pump discharge pressure 1. Unload solenoid not working Disassemble and clean by washing.
will not build up Replace solenoid as necessary.
2. Sticky plunger in proportioning Disassemble and clean by washing.
solenoid of reducing valve, or If the plunger is sticky, replace the solenoid.
sticky shuttle in reducing valve
3. Open in lead wire or in solenoid Repair or replace.
coil
4. Input current to solenoid too Check to make sure that solenoid is drawing
small specified maximum input current.
5. Unload valve stuck open • Check unload solenoid for action.
• Check unload valve for action.
6. Spool stuck in flow-divider Disassemble and clean by washing.
valve
Sticky spool Sticky plunger in proportioning Disassemble and clean by washing.
solenoid of reducing valve, or If plunger is sticky, replace solenoid.
sticky shuttle in reducing valve.
LED System
Component Trouble Condition ON-OFF Threshold Action check
pattern lamp
1 – – Normal A – No action OFF
2 Control levers Not in neutral Control levers are not in their D 128 ± 10 Turn off corresponding Flash
(1) Lift lever neutral positions when power (A/D value) solenoids’ outputs.
(2) Tilt lever supply is turned on.
(3) Attachment 1 lever Open circuit Input level is higher than lever B 245 to 255 Turn off corresponding ON
(4) Attachment 2 lever maximum position level. (A/D value) solenoids’ outputs.
Short circuit Input level is lower than lever B 0 to 10 Turn off corresponding ON
minimum position level. (A/D value) solenoids’ outputs.
3 Solenoids Open circuit Abnormal if current is 0 C 120 mA or Turn off abnormal ON
(1) Lift when solenoid output is ON. lower solenoid’s output.
(2) Tilt Short circuit Abnormal if solenoid output C 2.4 A or Turn off abnormal ON
(3) Attachment 1 current level is higher than higher solenoid’s output.
(4) Attachment 2 threshold level.
Leakage Abnormal current is detected C 140 mA or Turn off all solenoids’ ON
during emergency operation. higher outputs.
4 Seat switch Open circuit Check I/O levels. Abnormal E OFF for 15 Turn off all solenoids’ Flash
if signal stays OFF. seconds or outputs.
longer
5 CPU Abnormality (CPU does not run.) F – Turn off all solenoids’ Irregular
(WDT causes CPU reset.) outputs.
6 Battery voltage Voltage drop, Voltage is out of specification C Lower than 10 V; Turn off all solenoids’ ON
overvoltage higher than 32 V outputs.
7 Setting switch Check mode Setting of SW 2 (DIP switch) G S1 ON Start check mode (OFF)
operation
(solenoid operation)

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