This document contains Ford OBD1 diagnostic codes for various vehicle systems. It includes 2-digit and 3-digit codes with descriptions of what each code indicates, such as a specific cylinder failing a balance test, various sensor issues, transmission problems, and more. The codes are organized into tables with the code number, what system it applies to, and a definition of the issue detected.

1. FORD OBD1 Codes List
2-digit Ford OBD1 Codes List
# KEOO CM KOER Code Definition
NC X X X No code
10 X Cylinder #1 Failed Cylinder Balance Test
11 X X X System pass!
12 X Cannot control RPM during ER Self-Test high RPM check.
13 X Cannot control RPM during ER Self-Test low RPM check.
14 X
Two or more successive erratic Profile Ignition Pickup (PIP) pulses occurred, resulting in a
possible engine miss or stall.
15 X EEC permanent Read Only Memory (ROM) test failed.
15 X EEC battery powered Keep Alive Memory (KAM) test failed.
16 X IDM signal not received.
16 X RPM too low to perform HEGO test.
17 X RPM below Self-Test limit with Idle Air Control off
18 X SPOUT circuit open or spark angle word failure.
18 X IDM circuit failure or SPOUT circuit grounded
19 X Failure in EEC internal voltage.
19 X Cylinder Identification CID circuit failure.
19 X RPM erratic, dropped too low during test.
20 X Cylinder #2 Failed Cylinder Balance Test.
21 X X X ECT out of self test range 0.3 to 3.7 volts.
22 X X X MAP/BP sensor out of self test range
23 X X Closed throttle TPS voltage higher or lower than expected
24 X X X ACT sensor out of self test range 0.3 to 3.7 volts.
25 X Knock not sensed during dynamic test
26 X MAF sensor was greater than 0.7 volts with engine off
26 X MAF sensor was not between 0.2 and 1.5 volts with engine running.
26 X X TOT sensor out of self test range.
27 ?
28 X X VAT sensor out of self test range.
28 X Loss of IDM, right side.
29 X Insufficient input from vehicle speed sensor

2. 30 X Cylinder #3 Failed Cylinder Balance Test.
31 X X PFE or EVP circuit below minimum voltage of 0.24 volts
31 X PFE or EVP circuit has intermittently failed below minimum voltage of 0.24 volts.
32 X X EVP circuit below minimum voltage of 0.24 volts.
32 X EVP circuit has intermittently failed below minimum voltage of 0.24 volts.
33 X X EGR valve opening not detected
34 X X PFE or EVP circuit above the closed limit of 0.67 volts
34 X PFE or EVP circuit has intermittently failed above the closed limit of 0.67 volts.
35 X X PFE or EVP circuit above the maximum limit of 4.81 volts.
35 X PFE or EVP circuit has intermittently failed above the maximum limit of 4.81 volts
39 X AXOD converter bypass clutch not applying properly
40 X Cylinder #4 Failed Cylinder Balance Test.
41 X HEGO sensor circuit indicates system lean (right side).
41 X No HEGO switching detected always lean (right side).
42 X HEGO sensor circuit indicates system rich (right side).
42 X No HEGO switching detected always rich (right side).
43 X HEGO lean at Full Throttle.
44 X X Thermactor Air Injection system inoperative (Right side).
45 X DIS coil pack 3 circuit failure or coil 1 primary circuit failure.
45 X Thermactor secondary air is misdirected
46 X DIS coil pack 1 circuit failure or coil 2 primary circuit failure.
46 X Thermactor air not bypassed during self test.
47 X 4WD switch closed.
47 X Measured air flow too low at base idle
48 X Loss of IDM, left side.
48 X Measured air flow too high at base idle
49 X SPOUT signal default to 10 BTDC.
49 X 1 - 2 shift error (E4OD).
50 X Cylinder #5 Failed Cylinder Balance Test.
51 X X ECT sensor signal is greater than the Self-Test maximum of 4.6 volts.
52 X X X Power steering pressure switch always open or closed.
53 X TPS circuit above maximum 4.5 volts.
53 X TPS circuit has intermittently failed above maximum 4.5 volts.
54 X X ACT sensor signal is greater than the Self-Test maximum of 4.6 volts.

3. 55 X Keyed power input to processor is open.
56 X X MAF circuit above maximum voltage of 4.5volts.
56 X X TOT sensor output is greater than Self-Test maximum value of 4.8 volts.
57 X Octane adjust service pin in use / circuit grounded.
57 X AXOD Neutral pressure switch circuit failed open.
58 X X VAT indicated -40F / circuit open.
59 X X Low speed fuel pump circuit failure.
59 X X 2 - 3 shift error (E4OD).
60 X Cylinder #6 Failed Cylinder Balance Test.
61 X ECT sensor is less than the Self-Test minimum of 0.2 volts
61 X ECT sensor has intermittently failed below 0.2 volts
62 X 4/3 or 3/2 pressure switch circuit failed open
62 X Converter clutch error (E4OD).
63 X TPS circuit below minimum 0.6 volts
63 X TPS circuit has intermittently failed below minimum 0.6 volts.
64 X ACT sensor is less than the Self-Test minimum of 0.2 volts.
64 X ACT sensor has intermittently failed below 0.2 volts.
65 X Overdrive OFF switch was not cycled during KOER test (user error).
66 X MAF sensor went below 0.4 volts during the last 80 warm-up cycles.
66 X X TOT sensor output was less than Self-Test minimum value of 0.15 volts.
67 X X Neutral safety circuit failure
67 X A/C circuit was on during KOER Self-Test
68 X Transmission recently overheated, or TOT sensor intermittently failed below 0.2 volts.
69 X 3 - 4 shift error.
70 X Cylinder #7 Failed Cylinder Balance Test.
71 X Software re-initialization detected or Cluster ControlAssembly circuit failed
72 X Power interruption detected or Message Center Control Assembly circuit failed.
72 X Insufficient MAF/MAP change during Dynamic Response Test (user error).
73 X TPS senor did not exceed 25% rotation during Dynamic Response Test (user error)
74 X Brake On/Off switch not actuated during KOER test (user error).
75 X Brake On/Off switch failure always ON.
76 X Insufficient VAT change during Dynamic Response Test (user error)
77 X System failed to recognize brief WOT during Dynamic Response Test (user error)
79 X A/C or defrost on during self test.

4. 80 X Cylinder #8 Failed Cylinder Balance Test
81 X Air management 2 circuit failure (AM2/TAD).
81 X MAP sensor vacuum was not greater than 2 in-Hg (7 kPa) during normal vehicle operation
82 X Air management 1 circuit failure (AM1/TAB) .
83 X EGR Control solenoid circuit failure.
83 X High speed electro-drive fan circuit failure.
83 X X Low speed fuel pump relay circuit open
84 X X EGR Vacuum Solenoid circuit failure.
85 X X Canister Purge Solenoid circuit failure.
86 X 3 4 Shift solenoid circuit failure.
86 X Adaptive fuel limit reached.
87 X
Fuel pump primary circuit failure. When the FP relay was activated by the EEC, voltage was not
detected on the control circuit.
87 X Voltage was not detected on Fuel Pump Monitor while the engine was running.
88 X Electro-drive fan circuit failure.
88 X Loss of dual plug input control
89 X Converter clutch solenoid circuit failure.
90 X All cylinders passed Cylinder Balance Test.
91 X Shift solenoid 1 circuit failure (E4OD).
91 X No HEGO switching detected always lean (left side).
91 X HEGO sensor circuit indicates system lean (left side).
92 X Shift solenoid 2 circuit failure (E4OD).
92 X No HEGO switching detected always rich (left side).
92 X HEGO sensor circuit indicates system rich (left side).
93 X Coast clutch solenoid circuit failure (E4OD).
94 X Converter clutch solenoid circuit failure (E4OD).
94 X Thermactor Air Injection system inoperative (left side).
95 X X
Fuel pump secondary circuit failure. The EEC senses infinite resistance to ground from the fuel
pump on the Fuel Pump Monitor circuit.
96 X X
Fuel pump secondary circuit failure. The EEC did not sense battery voltage on the Fuel Pump
Monitor circuit.
97 X Overdrive cancel indicator light circuit failure (E4OD)
98 X X Electronic pressure control driver open in EEC (E4OD).
98 X Hard fault present
99 X X Electronic pressure control circuit failure (E4OD).

5. 99 X EEC system hasnt learned to control idle.
3-digit Ford OBD1 Codes List
# KOEO CM KOER 3-Digit Code Definitions
NC X X X No Codes
111 X X X System pass
112 X
ACT sensor signal is less than the Self-Test minimum of
0.2 volts
112 X
ACT circuit has intermittently failed below minimum 0.2
volts.
113 X
ACT sensor signal is greater than the Self-Test
maximum of 4.6 volts.
113 X
ACT circuit has intermittently failed above the
maximum of 4.6 volts
114 X X ACT out of self test range 0.3 to 3.7 volts.
116 X X ECT out of self test range 0.3 to 3.7 volts.
117 X
ECT sensor signal is less than the Self-Test minimum of
0.2 volts.
117 X
ECT circuit has intermittently failed below minimum 0.2
volts.
118 X
ECT sensor signal is greater than the Self-Test maximum
of 4.6 volts.
118 X
ECT circuit has intermittently failed above the maximum
of 4.6 volts
121 X X
Closed throttle TPS voltage higher or lower than
expected.
121 X
TP sensor was inconsistent with the MAF/MAP value in
the last 80 drive cycles.
122 X TPS circuit below minimum 0.6 volts.
122 X
TPS circuit has intermittently failed below minimum 0.6
volts.
123 X TP circuit above maximum 4.5 volts.
123 X
TPS circuit has intermittently failed above maximum 4.5
volts.
124 X
TP sensor was higher than expected with the MAF/MAP
value in the last 80 drive cycles.

6. 125 X
TP sensor was lower than expected with the MAF/MAP
value in the last 80 drive cycles
126 X X X MAP/BP sensor out of self test range 1.4 to 1.6 volts.
128 X
MAP sensor vacuum was not greater than 2 in-Hg (7
kPa) during normal vehicle operation.
129 X
Insufficient MAF/MAP change during Dynamic
Response Test.
136 X HEGO sensor circuit indicates system lean (left side)
137 X HEGO sensor circuit indicates system rich (left side)
139 X No HEGO sensor switching detected or disconnected (left side)
141 X HEGO sensor circuit indicates system lean (both sides)
144 X
No HEGO sensor switching detected or disconnected
(right side)
157 X
MAF sensor went below 0.4 volts during the last 80
warm-up cycles.
158 X X
MAF sensor went above 4.5 volts during the last 80
warm-up cycles.
159 X MAF signal was greater than 0.70 volt during KOEO.
159 X
MAF signal was not between 0.20 and 1.50 volts during
KOER.
167 X
TPS did not exceed 25% rotation during the Dynamic
Response Test.
171 X
Fuel system at adaptive limit, HEGO unable to switch
(right side)
172 X HEGO sensor circuit indicates system lean (right side)
173 X HEGO sensor circuit indicates system rich (right side)
174 X HEGO switching time is slow
175 X
Fuel system at adaptive limit, HEGO unable to switch
(left side)
176 X HEGO sensor circuit indicates system lean (left side)
177 X HEGO sensor circuit indicates system rich (left side)
178 X HEGO switching time is slow
179 X
Right side still rich, at leanest adaptive limit, during part
throttle.
181 X
Right side still lean, at richest adaptive limit, during part
throttle.
182 X Right side still rich, at leanest adaptive limit, at idle.

7. 183 X Right side still lean, at richest adaptive limit, at idle.
184 X MAF higher than expected
185 X MAF lower than expected
186 X Injector pulse width longer than expected
187 X Injector pulse width shorter than expected
188 X
Left side still rich, at leanest adaptive limit, during part
throttle.
189 X
Left side still lean, at richest adaptive limit, during part
throttle
191 X Left side still rich, at leanest adaptive limit, at idle.
192 X Left side still lean, at richest adaptive limit, at idle.
193 X Flexible Fuel sensor circuit failure
194 X Run cylinder balance diagnostic test.
195 X Run cylinder balance diagnostic test.
211 X
Two or more successive erratic Profile Ignition Pickup
(PIP) pulses occurred, resulting in a possible engine miss
or stall.
212 X Loss of IDM input to EEC or SPOUT circuit grounded.
213 X SPOUT circuit open
214 X Cylinder Identification (CID) circuit failure
215 X EEC detected coil 1 primary circuit failure
216 X EEC detected coil 2 primary circuit failure
217 X EEC detected coil 3 primary circuit failure
218 X Loss of IDM signal (left side)
219 X
SPOUT failure, spark timing has defaulted to 10 degrees
BTDC.
222 X Loss of IDM signal (right side)
223 X Loss of Dual Plug Inhibit control
224 X Erratic IDM input to processor
225 X
Knock Sensor (KS) signal not sensed during dynamic
response test.
226 X IDM signal not received
244 X Camshaft Position (CMP) Sensor failure.
311 X Thermactor air system inoperative (right side)
312 X Thermactor air misdirected upstream during self test

8. 313 X
Thermactor air not bypassed during self test.
314 X Thermactor air system inoperative (left side)
326 X X
PFE or DPFE circuit voltage lower than expected with
zero EVR duty cycle
327 X X X
DPFE or EVP circuit below minimum voltage of 0.2
volts.
328 X X X EVP circuit below minimum voltage of 0.24 volts.
332 X X EGR valve opening not detected.
334 X X X
DPFE or EVP circuit above the closed limit of 0.67
volts.
335 X PFE or DPFE sensor voltage out of Self-Test range.
336 X X
EVP or DPFE circuit voltage above maximum voltage
with zero EVR duty cycle.
337 X X X
DPFE or EVP circuit above the maximum limit of 4.81
volts.
338 X ECT lower than expected.
339 X ECT higher than expected.
341 X
Octane Adjust shorting bar is not in or the OCT ADJ
circuit is open.
381 X
Frequent A/C compressor clutch (ACCS) cycling less
than 8.5 seconds.
411 X Cannot control rpm during KOER low RPM check
412 X Cannot control rpm during KOER high RPM check
452 X
Computer detected an error in the VSS or PSOM signal
during the last 80 warm-up cycles
461 X Engine over speed was detected
511 X X X EEC permanent Read Only Memory (ROM) test failed.
512 X
EEC battery powered Keep Alive Memory (KAM) test
failed
513 X Failure in EEC processor internal voltage.
519 X Power steering pressure switch circuit open.
521 X
Power steering pressure switch did not change state
during KOER test
522 X Vehicle not in PARK or NEUTRAL during KOEO

9. 524 X X
When the PCM commanded the fuel pump on, voltage
was not detected on FPM.
525 X X Vehicle in gear or A/C on during Self-Test
526 X Neutral Pressure Switch closed or A/C on
527 X Neutral Drive Switch open or A/C on
528 X Clutch Switch Circuit failure
529 X
Data Communications Link or Electronic Instrument
Cluster circuit failure.
532 X
Data Communications Link or Electronic Instrument
Cluster circuit failure.
533 X
Data Communications Link or Electronic Instrument
Cluster circuit failure.
536 X X
Brake On/Off circuit failure / switch not actuated during
KOER test
538 X
Insufficient RPM change during KOER dynamic
response test/ Operator error
539 X A/C or Defroster ON during KOEO test
542 X X Fuel pump circuit failure
543 X X
When the PCM commanded the fuel pump on, voltage
was not detected on FPM.
551 X Intake Manifold Runner Control (IMRC) circuit failure
552 X Air management 1 circuit failure (AM1/TAB)
553 X Air management 2 circuit failure (AM1/TAD)
554 X
Fuel Pressure Regulator Control (FPRC) solenoid circuit
failure
556 X X Fuel Pump circuit failure
557 X X Fuel pump relay coil resistance failure
558 X EGR Vacuum Regulator circuit failure
559 X Air Conditioning On relay circuit failure
563 X High Speed Electro-Drive Fan circuit failure
564 X Electro-Drive Fan circuit failure
565 X Canister purge circuit failure
566 X 3 4 Shift Solenoid failure
569 X Canister purge 2 circuit failure
571 X EGR Atmospheric Regulator circuit failure.
572 X EGR Vacuum Regulator circuit failure.

10. 578 X
A/C Pressure (ACP) sensor VREF circuit is short to
ground.
579 X
A/C Pressure (ACP) sensor circuit is above maximum
voltage.
581 X
When the cooling fan was activated, the circuit exceeded
current draw.
582 X
Open or short to power in the power-to-cooling fan
circuit.
583 X
When the fuel pump was activated, the power-to-pump
circuit exceeded the normal current draw
584 X Variable Control Relay Module circuit grounded.
585 X A/C clutch circuit exceeded the normal current draw
586 X A/C clutch circuit open or shorted to power
587 X X Data Communications Link (DCL) error
593 X X Oxygen Sensor Heater circuit failure
617 X 1 - 2 shift error (E4OD)
618 X 2 - 3 shift error (E4OD)
619 X 3 - 4 shift error (E4OD)
621 X Shift solenoid #1 circuit failure
622 X Shift solenoid #2 circuit failure
623 X
Overdrive light circuit failure
624 X X
Electronic Pressure Control solenoid or driver circuit
failure
625 X X Electronic Pressure Control driver open in EEC
626 X Coast clutch solenoid circuit failure (E4OD)
627 X Converter clutch solenoid circuit failure (E4OD)
628 X Converter clutch Lock-Up error (E4OD)
629 X X Converter clutch control circuit failure
631 X Overdrive light circuit failure
632 X Overdrive cancel switch not changing state (E4OD)
633 X 4WD switch is closed
634 X X
Transmission Manual Lever Position Sensor circuit out
of self test.
636 X X TOT sensor voltage out of self test range.

11. 637 X X TOT sensor circuit above maximum voltage
638 X X TOT sensor circuit below minimum voltage
639 X X Insufficient input from the Transmission Speed Sensor
641 X Shift solenoid #3 circuit failure
643 X X Converter Clutch Control circuit failure
645 X Incorrect gear ratio obtained for first gear
646 X Incorrect gear ratio obtained for second gear
647 X Incorrect gear ratio obtained for third gear
648 X Incorrect gear ratio obtained for fourth gear
649 X Electronic Pressure Control range failure
651 X Electronic Pressure Control circuit failure
652 X Modulated Converter Clutch Control solenoid output circuit error
653 X
Transmission Control Switch was not cycled during
KOER Self-Test.
654 X MLP sensor not in park position
656 X Converter Clutch Control continuous slip error detected
657 X Transmission over temperature condition occurred.
659 X
High vehicle speed detected while the vehicle was in
PARK.
667 X
Transmission Manual Lever Position Sensor circuit
shorted
668 X Transmission Manual Lever Position Sensor circuit open
675 X MLP circuit voltage was out of the expected range
691 X 4WD switch circuit failure.
998 Hard fault present
NC X X X No Codes