8A - 2 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS ZJ Fig. 1 Starting System Components (Typical) All OBD-sensed systems are monitored by thePCM. Each monitored circuit is assigned a Diagnos-tic Trouble Code (DTC). The PCM will store a DTC inelectronic memory for any failure it detects. See Us-ing On-Board Diagnostic System in this group formore information. Fig. 2 Charging System Components (Typical)
ZJ BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 3 BATTERYGENERAL INFORMATION plates. If the battery cell caps cannot be removed, the The storage battery is a device used to store elec- battery must be replaced when the electrolyte level istrical energy potential in a chemical form. When an low.electrical load is applied to the battery terminals, anelectrochemical reaction occurs within the battery. WARNING: DO NOT ATTEMPT TO ASSIST BOOST,This reaction causes the battery to discharge electri- CHARGE, OR TEST BATTERY WHEN ELECTRO-cal current. LYTE LEVEL IS BELOW THE TOP OF THE PLATES. The battery is made up of 6 individual cells that PERSONAL INJURY MAY OCCUR.are connected in series. Each cell contains positivelycharged plate groups made of lead oxide, and nega-tively charged plate groups made of sponge lead. BATTERY RATINGSThese dissimilar metal plates are submerged in a Currently, there are 2 commonly accepted methodssulfuric acid and water solution called electrolyte. for rating and comparing battery performance. These As the battery discharges, a gradual chemical ratings are called Cold Cranking Amperage (CCA),change takes place within each cell. The sulfuric acid and Reserve Capacity (RC). Be certain that a replace-in the electrolyte combines with the plate materials, ment battery has CCA and RC ratings that equal orcausing both plates to change to lead sulfate. At the exceed the original equipment specification for thesame time, oxygen from the positive plate material vehicle being serviced. See Battery Classificationscombines with hydrogen from the sulfuric acid, caus- and Ratings charts in Specifications at the back ofing the electrolyte to become mainly water. this group. The chemical changes within the battery arecaused by movement of excess or free electrons be- COLD CRANKING AMPERAGEtween the positive and negative plate groups. This The Cold Cranking Amperage (CCA) rating speci-movement of electrons produces a flow of electrical fies how much current (in amperes) the battery cancurrent through the load device attached to the bat- deliver for 30 seconds at -17.7°C (0°F). Terminal volt-tery terminals. age must not fall below 7.2 volts during or after the As the plate materials become more similar chem- 30 second discharge. The CCA required is generallyically, and the electrolyte becomes less acid, the volt- higher as engine displacement increases, dependingage potential of each cell is reduced. However, by also upon the starter current draw requirements.charging the battery with a voltage higher than thatof the battery, the process is reversed. RESERVE CAPACITY Charging the battery gradually changes the sul- The Reserve Capacity (RC) rating specifies thefated lead plates back into sponge lead and lead ox- time (in minutes) it takes for battery terminal volt-ide, and the water back into sulfuric acid. This action age to fall below 10.2 volts at a discharge rate of 25restores the difference in electron charges deposited amps. RC is determined with the battery fully-on the plates, and the voltage potential of the battery charged at 26.7°C (80°F). This rating estimates howcells. long the battery might last after a charging system For a battery to remain useful, it must be able to failure, under minimum electrical load.produce high-amperage current over an extended pe-riod. A battery must also be able to accept a charge, DIAGNOSISso that its voltage potential may be restored. The battery must be completely charged and the In addition to producing and storing electrical en- top, posts, and terminal clamps should be properlyergy, the battery serves as a capacitor or voltage sta- cleaned before diagnostic procedures are performed.bilizer for the vehicle electrical system. It absorbs Refer to Group 8B - Battery/Starter/Generator Ser-abnormal or transient voltages caused by switching vice for more information.of any of the vehicle’s electrical components. The condition of a battery is determined by two cri- The battery is vented to release excess gas that is teria:created when the battery is being charged or dis- (1) State-Of-Charge This can be determined bycharged. However, even with these vents, hydrogen viewing the built-in test indicator, by checking spe-gas can collect in or around the battery. If hydrogen cific gravity of the electrolyte (hydrometer test), or bygas is exposed to flame or sparks, it can ignite. checking battery voltage (open circuit voltage test). If the electrolyte level is low, the battery could arc (2) Cranking Capacity This can be determinedinternally and explode. If the battery is equipped by performing a battery load test, which measureswith removable cell caps, add distilled water when- the ability of the battery to supply high-amperageever the electrolyte level is below the top of the current.
8A - 4 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS ZJ If the battery has a built-in test indicator, use thistest first. If it has no test indicator, but has remov-able cell caps, perform the hydrometer test first. Ifcell caps are not removable, or a hydrometer is notavailable, perform the open circuit voltage test first. The battery must be charged before proceedingwith a load test if:• the built-in test indicator has a black or dark colorvisible• the temperature corrected specific gravity is lessthan 1.235• the open circuit voltage is less than 12.4 volts. Fig. 3 Built-In Test Indicator A battery that will not accept a charge is faultyand further testing is not required. A battery that is Like a hydrometer, the built-in test indicator mea-fully-charged, but does not pass the load test is sures the specific gravity of the electrolyte. Specificfaulty and must be replaced. gravity will indicate battery state-of-charge. How- Completely discharged batteries may take ever, the test indicator will not indicate cranking ca-several hours to accept a charge. See Charging pacity of the battery. See Load Test in this group forCompletely Discharged Battery. more information. A battery is fully-charged when: Look into the sight glass and note the color of the• all cells are gassing freely during charging indicator (Fig. 4). Refer to the following description,• a green color is visible in the sight glass of the as the color indicates:built-in test indicator GREEN—indicates 75% to 100% state-of-charge.• three corrected specific gravity tests, taken at The battery is adequately charged for further test-1-hour intervals, indicate no increase in specific grav- ing or return to use. If the vehicle will not crank fority a minimum of 15 seconds with a fully-charged bat-• open circuit voltage is 12.4 volts or greater. tery, perform Load Test. BLACK OR DARK—indicates 0% to 75% state-of-ABNORMAL BATTERY DISCHARGING charge. Any of the following conditions can result in abnor- The battery is inadequately charged and must bemal battery discharging: charged until green indicator (Fig. 4) is visible in (1) Corroded battery posts and terminals. sight glass (12.4 volts or more) before the battery is (2) Loose or worn generator drive belt. tested further or returned to use. See Abnormal Bat- (3) Electrical loads that exceed the output of the tery Discharging in this group to diagnose cause ofcharging system, possibly due to equipment installed discharged condition.after manufacture or repeated short trip use. YELLOW OR BRIGHT—indicates low electrolyte (4) Slow driving speeds (heavy traffic conditions) or level.prolonged idling with high-amperage draw systems The electrolyte level in the battery is below test in-in use. dicator. A maintenance-free battery with non-remov- (5) Faulty circuit or component causing excessive able cell caps must be replaced if electrolyte level isignition-off draw. See Ignition-Off Draw in this group low. Water can be added to a low-maintenance bat-for diagnosis. tery with removable cell caps. A low electrolyte level (6) Faulty charging system. may be caused by an over-charging condition. See (7) Faulty or incorrect battery. Charging System in this group to diagnose an over- charging condition.BUILT-IN TEST INDICATOR A test indicator (hydrometer) built into the top of WARNING: DO NOT ATTEMPT TO CHARGE, TEST,the battery case, provides visual information for bat- OR ASSIST BOOST BATTERY WHEN YELLOW ORtery testing (Fig. 3). It is important when using the BRIGHT COLOR IS VISIBLE IN SIGHT GLASS OFtest indicator that the battery be level and have a TEST INDICATOR. LOW ELECTROLYTE LEVEL CANclean sight glass to see correct indications. Additional ALLOW BATTERY TO ARC INTERNALLY AND EX-light may be required to view indicator. PLODE. PERSONAL INJURY MAY OCCUR.WARNING: DO NOT USE OPEN FLAME AS ASOURCE OF ADDITIONAL LIGHT FOR VIEWING HYDROMETER TESTTEST INDICATOR. EXPLOSIVE HYDROGEN GAS The hydrometer test reveals the battery state-of-MAY BE PRESENT IN THE AREA SURROUNDING charge by measuring the specific gravity of the elec-BATTERY. trolyte. This test cannot be performed on batteries
ZJ BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 5 BATTERY DIAGNOSIS
8A - 6 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS ZJ Example: A battery is tested at -12.2°C (10°F) and has a specific gravity of 1.240. Determine the actual specific gravity as follows: (1) Determine the number of degrees above or be- low 26.7°C (80°F): 26.6°C - -12.2°C = 38.8°C (80°F - 10°F = 70°F) (2) Divide the result from step 1 by 5.5 (10): 38.8°C/5.5 = 7 (70°F/10 = 7) (3) Multiply the result from step 2 by the temper- ature correction factor (0.004): 7 x 0.004 = 0.028 Fig. 4 Built-In Test Indicator Sight Glass (4) The temperature at testing was below 26.7°C (80°F); therefore, the temperature correction is sub-with non-removable cell caps. If battery has non-re- tracted:movable cell caps, see Built-In Test Indicator or Open 1.240 - 0.028 = 1.212Circuit Voltage Test. The corrected specific gravity of the battery in this Specific gravity is a comparison of the density of example is 1.212.the electrolyte to the density of pure water. Pure wa- If the specific gravity of all cells is above 1.235, butter has a specific gravity of 1.000, and sulfuric acid variation between cells is more than 50 pointshas a specific gravity of 1.835. Sulfuric acid makes (0.050), the battery should be replaced.up approximately 35% of the electrolyte by weight, or If the specific gravity of one or more cells is less24% by volume. than 1.235, charge the battery at a rate of approxi- In a fully-charged battery the electrolyte will have mately 5 amperes. Continue charging until 3 consec-a temperature corrected specific gravity of 1.260 to utive specific gravity tests, taken at 1-hour intervals,1.290. However, a specific gravity of 1.235 or above is are constant. If the cell specific gravity variation issatisfactory for battery load testing and/or return to more than 50 points (0.050) at the end of the chargeservice. period, replace the battery. Before testing, visually inspect battery for any When the specific gravity of all cells is above 1.235,damage (cracked case or cover, loose posts, etc.) that and cell variation is less than 50 points (0.050), thewould cause the battery to be faulty. Then remove battery may be load tested.cell caps and check electrolyte level. Add distilled wa-ter if electrolyte level is below the top of the battery OPEN CIRCUIT VOLTAGE TESTplates. A battery open circuit voltage (no load) test will To use the hydrometer correctly, hold it with the show state-of-charge of a battery. This test can betop surface of the electrolyte at eye level. Refer to the used in place of the hydrometer test if a hydrometerhydrometer manufacturer’s instructions for correct is not available, or for maintenance-free batteriesuse of hydrometer. Remove only enough electrolyte with non-removable cell caps.from the battery so the float is off the bottom of the Before proceeding with this test or load test,hydrometer barrel with pressure on the bulb re- completely charge battery as described in Bat-leased. tery Charging in this group. Exercise care when inserting the tip of the hydrom- Test battery open circuit voltage as follows:eter into a cell to avoid damaging the plate separa- (1) Before measuring open circuit voltage the sur-tors. Damaged plate separators can cause premature face charge must be removed from the battery. Turnbattery failure. headlamps on for 15 seconds, then allow up to 5 min- Hydrometer floats are generally calibrated to indi- utes for voltage to stabilize.cate the specific gravity correctly only at 26.7°C (2) Remove both battery cables, negative first.(80°F). When testing the specific gravity at any other (3) Using a voltmeter connected to the batterytemperature, a correction factor is required. posts (refer to instructions provided with voltmeter) The correction factor is approximately a specific measure open circuit voltage (Fig. 5).gravity value of 0.004, referred to as 4 points of spe- See Open Circuit Voltage chart. This voltage read-cific gravity. For each 5.5°C above 26.7°C (10°F above ing will indicate state-of-charge, but will not reveal80°F), add 4 points. For each 5.5°C below 26.7°C cranking capacity. If a battery has an open circuit(10°F below 80°F), subtract 4 points. Always correct voltage reading of 12.4 volts or greater, it may bethe specific gravity for temperature variation. Test load tested. A battery that will not endure a load testthe specific gravity of the electrolyte in each battery is faulty and must be replaced.cell.
ZJ BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 7 OPEN CIRCUIT VOLTAGE Fig. 6 Volt-Amps-Load Tester (Typical) Fig. 5 Testing Open Circuit VoltageLOAD TEST A battery load test will verify battery cranking ca- Fig. 7 Volt-Ammeter-Load Tester Connectionspacity. The test is based on the Cold Cranking Am-perage (CCA) rating of the battery. See BatteryClassifications and Ratings chart in Specifications, atthe back of this group.WARNING: IF BATTERY SHOWS SIGNS OF FREEZ-ING, LEAKING, LOOSE POSTS, OR LOW ELECTRO-LYTE LEVEL, DO NOT LOAD TEST. PERSONALINJURY AND/OR VEHICLE DAMAGE MAY RESULT. Before performing load test, the battery mustbe FULLY-CHARGED. (1) Remove both battery cables, negative first. Bat-tery top and posts should be clean. (2) Connect a suitable volt-ammeter-load tester(Fig. 6) to the battery posts (Fig. 7). Refer to operat-ing instructions provided with the tester being used. Fig. 8 Remove Surface Charge from BatteryCheck the open circuit voltage (no load) of the bat- (5) Rotate the load control knob to maintain a loadtery. Open circuit voltage must be 12.4 volts or equal to 50% of CCA rating (Fig. 9). After 15 seconds,greater. record the loaded voltage reading, then return the (3) Rotate the load control knob (carbon pile rheo- load control knob to OFF.stat) to apply a 300 amp load for 15 seconds, then re- (6) Voltage drop will vary with battery tempera-turn the control knob to OFF (Fig. 8). This will ture at the time of the load test. Battery temperatureremove the surface charge from the battery. can be estimated by the ambient temperature over (4) Allow the battery to stabilize to open circuit the past several hours. If the battery has beenvoltage. It may take up to 5 minutes for voltage to charged, boosted, or loaded a few minutes prior tostabilize.
8A - 8 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS ZJ WARNING: POISONOUS AND CAUSTIC. BATTERY CONTAINS SULFURIC ACID. AVOID CONTACT WITH SKIN, EYES, OR CLOTHING. IN EVENT OF CON- TACT, FLUSH WITH WATER AND CALL PHYSICIAN IMMEDIATELY. KEEP OUT OF REACH OF CHIL- DREN. CAUTION: Always disconnect the battery negative cable before charging battery to avoid damage to electrical system components. Do not exceed 16.0 volts while charging battery. Battery electrolyte will bubble inside battery case during normal battery charging. If the electrolyte Fig. 9 Load 50% CCA Rating - Note Voltage boils, or is discharged from the vent holes while charging, immediately reduce charging rate or turntest, the battery will be somewhat warmer. See Load OFF charger and evaluate battery condition.Test Temperature chart for proper loaded voltage Battery should not be hot to the touch. If thereading. battery feels hot to the touch, turn OFF (7) If the voltmeter reading falls below 9.6 volts, at charger and let battery cool before continuinga minimum battery temperature of 21°C (70°F), re- charging operation.place the battery. Some battery chargers are equipped with polarity sensing circuitry. This circuitry protects the charger and/or battery from being damaged if improperly con- nected. If the battery state-of-charge is too low for the po- larity sensing circuitry to detect, the charger will not operate. This makes it appear that the battery will not accept charging current. Refer to instructions provided with the battery charger being used to by- pass the polarity sensing circuitry. BATTERY CHARGING TIME TABLEBATTERY CHARGING A battery is fully-charged when:• all cells are gassing freely during charging• a green color is visible in sight glass of built-intest indicator• three corrected specific gravity tests, taken at1-hour intervals, indicate no increase in specific grav-ity After the battery has been charged to 12.4 volts or greater, perform a load test to determine cranking• open circuit voltage is 12.4 volts or above. capacity. If the battery will endure a load test, returnWARNING: DO NOT ASSIST BOOST OR CHARGE A the battery to use. If the battery will not endure aBATTERY THAT HAS LOW ELECTROLYTE LEVEL load test, it must be replaced.OR IS FROZEN. BATTERY MAY ARC INTERNALLY Clean and inspect battery holddowns, tray, termi- nals, posts, and top before completing service. ReferAND EXPLODE. to Group 8B - Battery/Starter/Generator Service for more information.WARNING: EXPLOSIVE HYDROGEN GAS FORMS INAND AROUND BATTERY. DO NOT SMOKE, USE CHARGING TIME REQUIREDFLAME, OR CREATE SPARKS NEAR BATTERY. The time required to charge a battery will vary, de- pending upon the following factors:
ZJ BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 9 (1) Battery Capacity—A completely dischargedheavy-duty battery requires twice the rechargingtime of a small capacity battery.WARNING: NEVER EXCEED 20 AMPS WHENCHARGING A COLD (-1°C/30°F) BATTERY. PER-SONAL INJURY MAY RESULT. (2) Temperature—A longer time will be needed tocharge a battery at -18°C (0°F) than at 27°C (80°F).When a fast charger is connected to a cold battery,current accepted by the battery will be very low atfirst. As the battery warms, it will accept a highercharging current rate. (3) Charger Capacity—A charger that suppliesonly 5 amperes will require a longer charging time. A Fig. 10 Voltmeter Accurate to 1/10 Volt Connectedcharger that supplies 20 amperes or more requires a too low for the polarity sensing circuitry to detect,shorter charging time. the charger will not operate. This makes it appear (4) State-Of-Charge—A completely discharged that the battery will not accept charging current. Re-battery requires more charging time than a partially fer to the instructions provided with the batterydischarged battery. Electrolyte is nearly pure water charger to bypass the polarity sensing circuitry.in a completely discharged battery. At first, the (3) Battery chargers vary in the amount of voltagecharging current (amperage) will be low. As the bat- and current they provide. The amount of time re-tery charges, the specific gravity of the electrolyte quired for a battery to accept measurable chargerwill gradually rise. current at various voltages is shown in Charge RateCHARGING COMPLETELY DISCHARGED chart. If charge current is still not measurable at endBATTERY of charging times, the battery should be replaced. If The following procedure should be used to recharge charge current is measurable during charging time,a completely discharged battery. Unless this proce- the battery may be good and charging should be com-dure is properly followed, a good battery may be pleted in the normal manner.needlessly replaced. CHARGE RATE (1) Measure voltage at battery posts with a voltme-ter, accurate to 1/10 (0.10) volt (Fig. 10). If the read-ing is below 10 volts, the charge current will be low.It could take some time before the battery accepts acurrent greater than a few milliamperes. Such lowcurrent may not be detectable on ammeters built intomany chargers. (2) Disconnect battery negative cable. Connectcharger leads. Some battery chargers are equippedwith polarity sensing circuitry. This circuitry protectsthe charger and/or battery from being damaged if im-properly connected. If the battery state-of-charge is
8A - 10 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS ZJ IGNITION-OFF DRAWGENERAL INFORMATION The test lamp may light brightly for up to 3 min- Ignition-Off Draw (IOD) refers to power being utes, or may not light at all, depending upon the ve-drained from the battery with the ignition switch hicle’s electrical equipment. The term brightly, asturned OFF. A normal vehicle electrical system will used throughout the following tests, implies thedraw from 5 to 20 milliamps (0.005 - 0.020 amps). brightness of the test lamp will be the same as if itThis is with the ignition switch in the OFF position, were connected across the battery.and all non-ignition controlled circuits in proper The test lamp must be securely clamped to the neg-working order. The 20 milliamps are needed to sup- ative cable clamp and battery negative terminal. Ifply PCM memory, digital clock memory, and electron- the test lamp becomes disconnected during any partically-tuned radio memory. of the IOD test, the electronic timer function will be A vehicle that has not been operated for approxi- activated and all tests must be repeated.mately 20 days, may discharge the battery to an in- (5) After 3 minutes the test lamp should turn offadequate level. When a vehicle will not be used for or be dimly lit, depending upon the vehicle’s electri-20 days or more (stored), remove the IOD fuse in the cal equipment. If the test lamp remains brightly lit,Power Distribution Center (PDC). This will reduce do not disconnect it. Remove each fuse or circuitbattery discharging. breaker (refer to Group 8W - Wiring Diagrams) until Excessive battery drain can be caused by: test lamp is either off or dimly lit. This will isolate• electrical items left on each circuit and identify the source of the high-am-• faulty or improperly adjusted switches perage draw.• internally shorted generator• intermittent shorts in the wiring. If the test lamp is still brightly lit after disconnect- If the IOD is over 20 milliamps, the problem must ing each fuse and circuit breaker, disconnect the wir-be found and corrected before replacing a battery. In ing harness from the generator. If test lamp nowmost cases, the battery can be charged and returned turns off or is dimly lit, see Charging System in thisto service. group to diagnose faulty generator. Do not disconnect the test lamp.DIAGNOSIS After high-amperage IOD has been corrected, low- Testing for high-amperage IOD must be per- amperage IOD may be checked. It is now safe to in-formed first to prevent damage to most milli- stall a milliamp meter to check for low- amperageamp meters. IOD. (1) Verify that all electrical accessories are off. (6) With test lamp still connected securely, clamp aTurn off all lamps, remove ignition key, and close all milliamp meter between battery negative terminaldoors. If the vehicle is equipped with illuminated en- and negative cable clamp.try or electronically-tuned radio, allow the systems to Do not open any doors or turn on any electri-automatically shut off (time out). This may take up cal accessories with the test lamp disconnectedto 3 minutes. or the milliamp meter may be damaged. (2) Determine that the underhood lamp is operat- (7) Disconnect test lamp. Observe milliamp meter.ing properly, then disconnect or remove bulb. The current draw should not exceed 0.020 amp. If (3) Disconnect negative cable from battery. draw exceeds 20 milliamps, isolate each circuit by re- (4) Connect a typical 12-volt test lamp (low-watt- moving circuit breakers and fuses. The milliampage bulb) between the negative cable clamp and the meter reading will drop when the source of the drawbattery negative terminal. Make sure that the doors is disconnected. Repair this circuit as necessary,remain closed so that illuminated entry is not acti- whether a wiring short, incorrect switch adjustmentvated. or a component failure is found.
ZJ BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 11 STARTING SYSTEMGENERAL INFORMATION tion switch supplies battery voltage to the coil bat- The starting system (Fig. 11) consists of: tery terminal of the starter relay only if the clutch• ignition switch pedal is depressed while the ignition switch is turned• starter relay to the START position.• park/neutral position switch (automatic transmis- If the vehicle is equipped with an automatic trans-sion) mission, the park/neutral position switch provides a• clutch pedal position switch (manual transmission) ground path to the starter relay coil ground terminal.• wiring harness and connections This switch provides ground only with the transmis-• battery sion in NEUTRAL or PARK. If the vehicle is• starter with an integral solenoid. equipped with a manual transmission, the starter re- lay coil ground terminal is always grounded. With the starter relay coil now energized, the nor- mally open relay contacts close. The relay contacts connect the relay common feed terminal to the relay normally open terminal. The closed relay contacts en- ergize the starter solenoid coil windings. The energized solenoid coils pull-in and hold-in the solenoid plunger. The solenoid plunger pulls the shift lever in the starter. This engages the starter overrun- ning clutch and pinion gear with the flywheel/drive plate ring gear. As the solenoid plunger reaches the end of its travel, the solenoid contact disc completes the high- amperage starter feed circuit. Current now flows be- tween the solenoid battery terminal and the starter motor, energizing the starter. Once the engine starts, the overrunning clutch pro- tects the starter from damage by allowing the starter pinion gear to spin faster than the pinion shaft. When the driver releases the ignition switch to the ON position the starter relay coil is de-energized. This causes the relay contacts to open. When the re- lay contacts open, the starter solenoid coil is de-ener- gized. When the solenoid coil is de-energized, the solenoid plunger return spring returns the plunger to its re- laxed position. This causes the contact disc to open Fig. 11 Starting System Components (Typical) the starter feed circuit, and the shift lever to disen- Following is a general description of the major gage the overrunning clutch and pinion gear from thestarting system components. Refer to Group 8W - ring gear.Wiring Diagrams for complete circuit descriptions The starter motor and solenoid are serviced only asand diagrams. a complete assembly. If either component fails, the These components form 2 separate circuits. A high- entire assembly must be replaced.amperage feed circuit that feeds the starter up to300+ amps, and a low-amperage control circuit that DIAGNOSISoperates on less than 20 amps. Before removing any unit from the starting system If the vehicle is equipped with an automatic trans- for repair, perform the following inspections:mission, battery voltage is supplied through the low- INSPECTIONamperage control circuit to the coil battery terminalof the starter relay when the ignition switch is BATTERY INSPECTIONturned to the START position. If the vehicle isequipped with a manual transmission, it also has a To determine condition of the battery, see Batteryclutch pedal position switch. The clutch pedal posi- in this group.
8A - 12 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS ZJWIRING INSPECTION SOLENOID, RELAY AND SWITCH INSPECTIONS Inspect wiring for damage. Inspect all connections Inspect the solenoid, relay and ignition switch toat: determine their condition. Also, if equipped with au-• starter solenoid tomatic transmission, inspect condition of the park/• park/neutral position switch (automatic transmis- neutral position switch. If equipped with manualsion) transmission, inspect condition of the clutch pedal• clutch pedal position switch (manual transmission) position switch. Testing information can be found in• ignition switch the following pages.• starter relay• battery (including all ground connections). Clean, tighten and repair all connections as re-quired.
ZJ BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 13 STARTING SYSTEM DIAGNOSIS
8A - 14 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS ZJCOLD CRANKING TEST • unplug Auto Shut-Down (ASD) relay from Power (1) Battery must be fully-charged and load tested Distribution Center (PDC) to prevent engine frombefore proceeding. See Battery, in this group. starting (2) Connect a suitable volt-ampere tester to the • place transmission in NEUTRAL (manual trans-battery terminals (Fig. 12). Refer to the operating in- mission) or PARK (automatic transmission)structions provided with the tester being used. • install a jumper wire between two clutch pedal po- sition switch connectors (manual transmission) • parking brake is applied • battery is fully-charged (see Battery, in this group). (1) Connect positive lead of voltmeter to battery negative post. Connect negative lead of voltmeter to battery negative cable clamp (Fig. 13). Rotate and hold ignition switch in the START position. Observe voltmeter. If voltage is detected, correct poor contact between cable clamp and post. (2) Connect positive lead of voltmeter to battery positive post. Connect negative lead of voltmeter to battery positive cable clamp (Fig. 13). Rotate and hold ignition switch in the START position. Observe voltmeter. If voltage is detected, correct poor contact Fig. 12 Volt-Amps Tester Connections (Typical) between cable clamp and post. (3) Fully engage parking brake. Place manualtransmission in NEUTRAL and fully depress clutchpedal. Place automatic transmission in PARK. (4) Verify that all lamps and accessories are OFF. (5) Unplug Auto Shut-Down (ASD) relay fromPower Distribution Center (PDC) to prevent enginefrom starting. Relay location is shown on undersideof PDC cover. (6) Rotate and hold the ignition switch in theSTART position. Note cranking voltage and amper-age. (a) If voltage reads above 9.6 volts and amperage draw reads above specifications, see Feed Circuit Tests. (b) If voltage reads 12.5 volts or greater and am- perage reads below specifications, see Control Cir- Fig. 13 Test Battery Connection Resistance cuit Tests. (3) Connect voltmeter to measure between the bat- A cold engine will increase starter current tery positive post and the starter solenoid batteryand reduce battery voltage. stud (Fig. 14). Rotate and hold ignition switch in the START position. Observe voltmeter. If voltage readsFEED CIRCUIT TESTS above 0.2 volt, correct poor contact at battery cable to The starter feed circuit tests (voltage drop method) solenoid connection. Repeat test. If reading is stillwill determine if there is excessive resistance in the above 0.2 volt, replace battery positive cable.high-amperage circuit. When performing these tests, (4) Connect voltmeter to measure between the bat-it is important that the voltmeter be connected prop- tery negative post and a good clean ground on theerly. Connect voltmeter leads to the terminals that engine block (Fig. 15). Rotate and hold ignitionthe cable connectors or clamps are attached to, not to switch in the START position. Observe voltmeter. Ifthe cable connectors or clamps. For example: When voltage reads above 0.2 volt, correct poor contact attesting between the battery and solenoid, touch the battery negative cable attaching point. Repeat test. Ifvoltmeter leads to the battery post and the solenoid reading is still above 0.2 volt, replace battery nega-threaded stud. tive cable. The following operation will require a voltmeter ac- (5) Connect positive lead of voltmeter to startercurate to 1/10 (0.10) volt. Before performing the tests, housing. Connect negative lead of voltmeter to bat-be certain the following procedures are accomplished: tery negative terminal (Fig. 16). Rotate and hold ig-
ZJ BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 15 CONTROL CIRCUIT TESTS The starter control circuit consists of: • starter solenoid • starter relay • ignition switch • park/neutral position switch (automatic transmis- sion) • clutch pedal position switch (manual transmission) • wiring harness and connections. Test procedures for these components are as fol- lows, and should be followed in the order described. CAUTION: Before performing any test, unplug Auto Shut-Down (ASD) relay from Power Distribution Fig. 14 Test Battery Positive Cable Resistance Center (PDC) to prevent engine from starting. (Typical) SOLENOID TEST Refer to Group 8B - Battery/Starter/Generator Ser- vice for starter removal procedures. (1) Disconnect solenoid field coil wire from field coil terminal. (2) Check for continuity between solenoid terminal and field coil terminal with a continuity tester. There should be continuity (Fig. 17). Fig. 15 Test Ground Circuit Resistancenition switch in the START position. Observevoltmeter. If voltage reads above 0.2 volt, correct poor Fig. 17 Continuity Test Between Solenoid Terminalstarter to engine ground. and Field Coil Terminal (3) Check for continuity between solenoid terminal and solenoid case. There should be continuity (Fig. 18). Fig. 18 Continuity Test Between Solenoid Terminal and Solenoid Case Fig. 16 Test Starter Ground (Typical) (4) If there is continuity, solenoid is good. If there is no continuity in either test, solenoid has an open If resistance tests detect no feed circuit problems, circuit and is faulty. Replace starter assembly.remove the starter and see Solenoid Test in this (5) Connect solenoid field coil wire to field coil ter-group. minal. (6) Install starter as described in Group 8B - Bat- tery/Starter/Generator Service.
8A - 16 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS ZJRELAY TEST STARTER RELAY CONNECTIONS The starter relay is in the Power Distribution Cen-ter (PDC)(Fig. 19). Refer to the underside of the PDCcover for relay location. Remove starter relay from PDC to perform the fol-lowing tests: (1) A relay in the de-energized position shouldhave continuity between terminals 87A and 30, andno continuity between terminals 87 and 30. If OK, goto next step. If not OK, replace faulty relay. (2) Resistance between terminals 85 and 86 (elec-tromagnet) should be 75Ϯ5 ohms. If OK, go to nextstep. If not OK, replace faulty relay. (3) Connect a battery to terminals 85 and 86.There should now be continuity between terminals30 and 87, and no continuity between terminals 87Aand 30. If OK, go to Relay Circuit Test. If not OK, solenoid field coils. There should be continuity be-replace faulty relay. tween cavity for relay terminal 87 and the starter so- lenoid terminal at all times. If OK, go to next step. If not OK, repair circuit to solenoid as required. (4) The coil battery terminal (86) is connected to the electromagnet in the relay. It is energized when the ignition switch is in the START position. Check for battery voltage at cavity for relay terminal 86 with ignition switch in the START position. If OK, go to next step. If not OK and vehicle has automatic transmission, refer to Group 8D - Ignition Systems for testing and service of the ignition switch. If not OK and vehicle has manual transmission, refer to Group 6 - Clutch for testing and service of the clutch pedal position switch. (5) The coil ground terminal (85) is connected to the electromagnet in the relay. On vehicles with an automatic transmission, it is grounded through the park/neutral position switch. On vehicles with a manual transmission, it is grounded at all times. Check for continuity to ground at cavity for relay ter- minal 85. If not OK and vehicle has manual trans- mission, repair circuit as required. If not OK and vehicle has automatic transmission, refer to Group Fig. 19 Power Distribution Center 21 - Transmission and Transfer Case for testing and service of the park/neutral position switch.RELAY CIRCUIT TEST (1) The common feed terminal (30) is connected to IGNITION SWITCH TESTbattery voltage and should be hot at all times. If OK, Refer to Group 8D - Ignition Systems for testinggo to next step. If not OK, check circuit to fuse F12 and service of this component.in Power Distribution Center (PDC). Repair as re-quired. PARK/NEUTRAL POSITION SWITCH TEST (2) The normally closed terminal (87A) is con- Refer to Group 21 - Transmission and Transfernected to terminal 30 in the de-energized position, Case for testing and service of this component.but is not used for this application. Go to next step. (3) The normally open terminal (87) is connected to CLUTCH PEDAL POSITION SWITCH TESTthe battery terminal (30) in the energized position. Refer to Group 6 - Clutch for testing and service ofThis terminal supplies battery voltage to the starter this component.
ZJ BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 17 CHARGING SYSTEMGENERAL INFORMATION The charging system consists of:• generator• voltage regulator circuitry (within PCM)• ignition switch• battery• voltmeter• wiring harness and connections. Following is a general description of the majorcharging system components. Refer to Group 8W -Wiring Diagrams for complete circuit descriptionsand diagrams. The charging system is turned on and off with theignition switch. When the ignition switch is turned tothe ON position, battery voltage is applied to thegenerator rotor through one of the two field termi-nals to produce a magnetic field. The generator isdriven by the engine through a serpentine belt andpulley arrangement. As the energized rotor begins to rotate within thegenerator, the spinning magnetic field induces a cur-rent into the windings of the stator coil. Once thegenerator begins producing sufficient current, it alsoprovides the current needed to energize the rotor. The wye (Y) type stator winding connections de-liver the induced AC current to 3 positive and 3 neg-ative diodes for rectification. From the diodes,rectified DC current is delivered to the vehicle elec-trical system through the generator battery and Fig. 20 Charging System Components (Typical)ground terminals. The amount of DC current produced by the gener- DIAGNOSISator is controlled by the generator voltage regulator When the ignition switch is turned to the ON posi-(field control) circuitry, contained within the Power- tion, battery potential will register on the voltmeter.train Control Module (PCM)(Fig. 20). This circuitry is During engine cranking a lower voltage will appearconnected in series with the second rotor field termi- on the meter. With the engine running, a voltagenal and ground. reading higher than the first reading (ignition in ON) Voltage is regulated by cycling the ground path to should register.control the strength of the rotor magnetic field. The The following procedures may be used to diagnosegenerator voltage regulator circuitry monitors system the charging system if:line voltage and ambient temperature. It then com- • the voltmeter does not operate properlypensates and regulates generator current output ac- • an undercharged or overcharged battery condition oc-cordingly. curs. The generator is serviced only as a complete as- Remember that an undercharged battery is oftensembly. If the generator fails for any reason, the en- caused by:tire assembly must be replaced. The generator • accessories being left on with the engine not runningvoltage regulator (field control) circuitry can be ser- • a faulty or improperly adjusted switch that allows aviced only by replacing the entire PCM. lamp to stay on (see Ignition-Off Draw in this group). All vehicles are equipped with On-Board Diagnos-tics (OBD). All OBD-sensed systems, including the INSPECTIONgenerator voltage regulator (field control) circuitry, (1) Inspect condition of battery cable terminals,are monitored by the PCM. Each monitored circuit is battery posts, connections at engine block, starter so-assigned a Diagnostic Trouble Code (DTC). The PCM lenoid and relay. They should be clean and tight. Re-will store a DTC in electronic memory for any failure pair as required.it detects. See Using On-Board Diagnostic System in (2) Inspect all fuses in the fuseblock module andthis group for more information. Power Distribution Center (PDC) for tightness in re-
8A - 18 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS ZJceptacles. They should be properly installed and OUTPUT WIRE RESISTANCE TESTtight. Repair or replace as required. This test will show the amount of voltage drop (3) Inspect the electrolyte level in the battery. If across the generator output wire, from the generatorcell caps are removable, add water if required. If cell battery terminal to the battery positive post.caps are not removable, replace battery if electrolytelevel is low. PREPARATION (4) Inspect generator mounting bolts for tightness. (1) Before starting test make sure vehicle has aReplace or tighten bolts, if required. Refer to Group fully-charged battery. See Battery in this group for8B - Battery/Starter/Generator Service for torque more information. (2) Turn ignition switch to OFF.specifications. (3) Disconnect negative cable from battery. (5) Inspect generator drive belt condition and tension. (4) Disconnect generator output wire from genera-Tighten or replace belt as required. Refer to Belt Ten- tor battery output terminal.sion Specifications in Group 7 - Cooling System. (5) Connect a 0-150 ampere scale DC ammeter (6) Inspect connections at generator field, battery (Fig. 21). Install in series between generator batteryoutput, and ground terminals. Also check ground con- output terminal and disconnected generator outputnection at engine. They should all be clean and tight. wire. Connect positive lead to generator battery out-Repair as required. put terminal and negative lead to disconnected gen- erator output wire. CHARGING SYSTEM DIAGNOSIS
ZJ BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 19 Fig. 21 Generator Output Wire Resistance Test (Typical) (6) Connect positive lead of a test voltmeter (range tion between generator battery output terminal and bat-0-18 volts minimum) to disconnected generator out- tery positive post. A voltage drop test may be performedput wire. Connect negative lead of test voltmeter to at each connection to locate the connection with exces-battery positive cable at positive post. sive resistance. If resistance tests satisfactorily, reduce (7) Connect one end of a jumper wire to ground engine speed, turn OFF carbon pile and turn OFF igni-and with other end probe green K20 field wire at tion switch.back of generator (Fig. 21). This will generate a DTC. (1) Disconnect negative cable from battery. (2) Remove test ammeter, voltmeter, carbon pile,CAUTION: Do not connect green/orange A142 field and tachometer.wire to ground. Refer to Group 8W - Wiring Dia- (3) Remove jumper wire.grams for more information. (4) Connect generator output wire to generator (8) Connect an engine tachometer, then connect battery output terminal. Tighten nut to 8.5Ϯ1.5 N⅐mbattery negative cable to battery. (75Ϯ15 in. lbs.). (9) Connect a variable carbon pile rheostat be- (5) Connect negative cable to battery.tween battery terminals. Be sure carbon pile is in (6) Use DRB scan tool to erase DTC.OPEN or OFF position before connecting leads. SeeLoad Test in this group for instructions. CURRENT OUTPUT TEST The generator current output test determines whetherTEST generator can deliver its rated current output. (1) Start engine. Immediately after starting, re-duce engine speed to idle. PREPARATION (2) Adjust engine speed and carbon pile to maintain (1) Before starting test make sure vehicle has a20 amperes flowing in circuit. Observe voltmeter read- fully-charged battery. See Battery in this group foring. Voltmeter reading should not exceed 0.5 volts. more information. (2) Disconnect negative cable from battery.RESULTS (3) Disconnect generator output wire at the gener- If a higher voltage drop is indicated, inspect, clean ator battery output terminal.and tighten all connections. This includes any connec-
8A - 20 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS ZJ (4) Connect a 0-150 ampere scale DC ammeter (2) Adjust carbon pile and engine speed in incre-(Fig. 22). Install in series between generator battery ments until a speed of 1250 rpm and voltmeter read-output terminal and disconnected generator output ing of 15 volts is obtained.wire. Connect positive lead to generator battery out-put terminal and negative lead to disconnected gen- CAUTION: Do not allow voltage meter to read aboveerator output wire. 16 volts. (5) Connect positive lead of a test voltmeter (range 0-18volts minimum) to generator battery output terminal. (3) The ammeter reading must be within limits (6) Connect negative lead of test voltmeter to a shown in Generator Output Voltage Specifications.good ground. (7) Connect an engine tachometer, then connect RESULTSbattery negative cable to battery. (1) If reading is less than specified and generator (8) Connect a variable carbon pile rheostat be- output wire resistance is not excessive, generatortween battery terminals. Be sure carbon pile is in should be replaced. Refer to Group 8B - Battery/OPEN or OFF position before connecting leads. See Starter/Generator Service.Load Test in this group for instructions. (2) After current output test is completed, reduce (9) Connect one end of a jumper wire to ground engine speed, turn OFF carbon pile and turn OFF ig-and with other end probe green K20 field wire at nition switch.back of generator (Fig. 22). This will generate a DTC. (3) Disconnect negative cable from battery. (4) Remove test ammeter, voltmeter, tachometerCAUTION: Do not connect green/orange A142 field and carbon pile.wire to ground. Refer to Group 8W - Wiring Dia- (5) Remove jumper wire (Fig. 22).grams for more information. (6) Connect generator output wire to generator battery output terminal. Tighten nut to 8.5Ϯ1.5 N⅐mTEST (75Ϯ15 in. lbs.). (1) Start engine. Immediately after starting, re- (7) Connect negative cable to battery.duce engine speed to idle. (8) Use DRB scan tool to erase DTC. Fig. 22 Generator Current Output Test (Typical)
ZJ BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 21 USING ON-BOARD DIAGNOSTIC SYSTEMGENERAL INFORMATION to be set. Therefore, it is important that the test pro- The Powertrain Control Module (PCM) monitors cedures be followed in sequence, to understand whatcritical input and output circuits of the charging sys- caused a DTC to be set.tem, making sure they are operational. A Diagnostic See Generator Diagnostic Trouble Code chart forTrouble Code (DTC) is assigned to each input and DTC’s which apply to the charging system. Refer tooutput circuit monitored by the OBD system. Some the Powertrain Diagnostic Procedures manual to di-circuits are checked continuously and some are agnose an on-board diagnostic system trouble code.checked only under certain conditions. If the OBD system senses that a monitored circuit RETRIEVING DIAGNOSTIC TROUBLE CODESis bad, it will put a DTC into electronic memory. The To start this function, cycle the ignition switch ON-DTC will stay in electronic memory as long as the OFF-ON-OFF-ON within 5 seconds. This will causecircuit continues to be bad. The PCM is programmed any DTC stored in the PCM memory to be displayed.to clear the memory after 50 engine starts, if the The malfunction indicator (Check Engine) lamp willproblem does not occur again. display a DTC by flashing on and off. There is a short pause between flashes and a longer pause be-DIAGNOSTIC TROUBLE CODES tween digits. All DTC’s displayed are two-digit num- Diagnostic Trouble Codes (DTC) are two-digit num- bers, with a four-second pause between codes.bers flashed on the malfunction indicator (Check En- An example of a DTC is as follows:gine) lamp that identify which circuit is bad. A DTC (1) Lamp on for 2 seconds, then turns off.description can also be read using the DRB scan tool. (2) Lamp flashes 4 times pauses and then flashes 1Refer to Group 14 - Fuel Systems for more informa- time.tion. (3) Lamp pauses for 4 seconds, flashes 4 times, A DTC does not identify which component in a cir- pauses, then flashes 7 times.cuit is bad. Thus, a DTC should be treated as a The two DTC’s are 41 and 47. Any number ofsymptom, not as the cause for the problem. In some DTC’s can be displayed, as long as they are in mem-cases, because of the design of the diagnostic test ory. The lamp will flash until all stored DTC’s areprocedure, a DTC can be the reason for another DTC displayed (55 = end of test). GENERATOR DIAGNOSTIC TROUBLE CODE
8A - 22 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS ZJ SPECIFICATIONSBATTERY SPECIFICATIONS STARTER AND SOLENOID TESTING SPECIFICATIONS BATTERY CLASSIFICATIONS AND RATINGSSTARTING SYSTEM SPECIFICATIONS STARTER SPECIFICATIONS STARTING SYSTEM COLD CRANKING SPECIFICATIONS CHARGING SYSTEM SPECIFICATIONS OUTPUT VOLTAGE SPECIFICATIONS GENERATOR RATINGS