Charging System - Generators & Regulators: Diagnosis Jeep Cherokee II рестайлинг

TROUBLE SHOOTING

Note. For additional trouble shooting, see TROUBLE SHOOTING article in GENERAL INFORMATION.

SELF-DIAGNOSTIC SYSTEM

If a problem is sensed in a monitored circuit, a Diagnostic Trouble Code (DTC) will be stored in PCM and MIL will come on, provided specific criteria are met. PCM will then enter limp-in mode, substituting information from other sources to compensate for component failure. Vehicle is operational in limp-in mode, but driveability may not be optimal.

A specific DTC results from a particular system failure. DTC only indicates problem circuit. It does not identify specific component failure in the circuit.

If problem is repaired or ceases to exist, PCM automatically clears DTC after 50 ignition on-off cycles. DTCs can also be cleared using scan tool. See CLEARING DTCS .

ON-BOARD DIAGNOSTICS

Note. PCM cannot diagnose every charging system problem. If fault still exists after performing self-diagnostic procedures, proceed to ON-VEHICLE TESTING .

Using Scan Tool

1. Ensure battery is fully charged. Connect scan tool to Data Link Connector (DLC). DLC is located below instrument panel, near steering column.
2. Using scan tool manufacturer's instructions, retrieve and record DTCs displayed on scan tool and proceed to «SELF-DIAGNOSTIC TESTS»(ref-670-S37527032182000031300000) . Once repairs are made, clear DTCs from PCM memory. See «CLEARING DTCS»(ref-670-S00787086812000031300000) .

SELF-DIAGNOSTIC TESTS

Note. When using diagnostic tests, DO NOT skip any steps in chart, or incorrect diagnosis may result. Ensure battery is fully charged.

DTC TEST: CHECKING SYSTEM FOR DIAGNOSTIC TROUBLE CODES

1. Attempt to start engine. If necessary, crank engine for up to 10 seconds. Read and record DTCs. See «RETRIEVING DTCS»(ref-670-S09189276322000031300000) under SELF-DIAGNOSTIC SYSTEM. If scan tool screen is blank or displays NO RESPONSE, see «SCAN TOOL PROBLEMS & ERROR MESSAGES»(ref-670-S20968372112000031300000) under SELF-DIAGNOSTIC SYSTEM.
2. If DTCs are displayed, see SCAN TOOL DTC MESSAGES table. Only DTCs relating to charging system are listed. For all other DTCs, see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE in the appropriate manual. If no DTCs are displayed, go to «TEST CH-1A: CHARGING SYSTEM NO CODE TEST»(ref-670-S40425239032000031300000).

SCAN TOOL DTC MESSAGES

TEST VER-2A: ROAD TEST VERIFICATION

1. If PCM has been replaced, go to next step. If ECM has been replaced or battery has been disconnected on diesel powered vehicles, go to step 3 . If neither module has been replaced, go to step 4 .
2. Connect scan tool to Data Link Connector (DLC). DLC is located below driver's side of instrument panel. Using scan tool, enter correct VIN and mileage into PCM. Using scan tool manufacturer's instructions, clear DTCs from ABS and SRS modules.
3. Programming of Accelerator Pedal Position Sensor (APPS) is necessary if ECM has been replaced or battery has been disconnected on diesel powered vehicles. Ensure all components are connected. Turn ignition on. Slowly depress accelerator pedal to floor, then slowly release. APPS is now programmed. Go to next step.
4. Inspect vehicle to ensure all engine components are connected. Reassemble and reconnect components as necessary.
5. Check if initial symptom still exists. If initial or another symptom exists, repair is not complete. Check for Technical Service Bulletins (TSBs) that apply to symptom.
6. If any DTCs have not been diagnosed, go to appropriate test and finish diagnosing remaining DTCs as necessary. If all DTCs have been diagnosed, go to next step.
7. Using scan tool, erase DTCs from PCM. Using scan tool, reset all values in adaptive memory. Disconnect scan tool. If no other DTCs remain, repair is now complete.

TEST VER-3A: CHARGING VERIFICATION

1. If PCM has been replaced, go to next step. If ECM has been replaced or battery has been disconnected on diesel powered vehicles, go to step 3 . If neither module has been replaced, go to step 4 .
2. Connect scan tool to Data Link Connector (DLC). DLC is located below driver's side of instrument panel. Using scan tool, enter correct VIN and mileage into PCM. Using scan tool manufacturer's instructions, clear DTCs from ABS and SRS modules.
3. Programming of Accelerator Pedal Position Sensor (APPS) is necessary if ECM has been replaced or battery has been disconnected on diesel powered vehicles. Ensure all components are connected. Turn ignition on. Slowly depress accelerator pedal to floor, then slowly release. APPS is now programmed. Go to next step.
4. Inspect vehicle to ensure all engine components are connected. Reassemble and reconnect components as necessary.
5. To ensure no charging system problem exists, start engine. Perform «OUTPUT VOLTAGE TEST»(ref-670-S20978039862000031300000) under ON-VEHICLE TESTING. Increase engine speed to 2000 RPM for at least 30 seconds. Allow engine to idle. Turn engine off.
6. Using scan tool, check for stored DTCs. If repaired DTC has reset, repair is not complete. Check for related Technical Service Bulletins (TSBs) and return to DTC TEST, if necessary. If another DTC exists, go to appropriate DTC test and follow specified procedure. If no other DTCs exist, repair is now complete.

TEST VER-5A: ROAD TEST VERIFICATION

1. If PCM has been replaced, go to next step. If ECM has been replaced or battery has been disconnected on diesel powered vehicles, go to step 3 . If neither module has been replaced, go to step 4 .
2. Connect scan tool to Data Link Connector (DLC). DLC is located below driver's side of instrument panel. Using scan tool, enter correct VIN and mileage into PCM. Using scan tool manufacturer's instructions, clear DTCs from ABS and SRS modules.
3. Programming of Accelerator Pedal Position Sensor (APPS) is necessary if ECM has been replaced or battery has been disconnected on diesel powered vehicles. Ensure all components are connected. Turn ignition on. Slowly depress accelerator pedal to floor, then slowly release. APPS is now programmed. Go to next step.
4. Connect scan tool to Data Link Connector (DLC). DLC is located below driver's side of instrument panel. Using scan tool, enter correct VIN and mileage into PCM. Using scan tool manufacturer's instructions, clear DTCs from ABS and SRS modules.
5. Inspect vehicle to ensure all engine components are connected. Reassemble and reconnect components as necessary.
6. If any DTCs have not been diagnosed, go to appropriate test and finish diagnosing remaining DTCs as necessary. If all DTCs have been diagnosed, go to next step.
7. Connect scan tool to DLC connector. Ensure fuel tank is at least 25 percent full. Turn off all accessories.
8. Using scan tool OBDII monitor, verify DTC repair. See scan tool instructions. Allow PCM to run appropriate monitor(s) and increment a global good trip (drive cycle). Enabling conditions must be met before PCM will run OBDII monitor. Scan tool monitor pretest screen will display enabling conditions.
9. If repaired DTC has reset or was seen in OBDII monitor while on road test, repair is not complete. Check for any TSBs and return to appropriate test. Repair as needed.
10. If any other DTCs are set, repair as needed. If OBDII monitor is run and good trip counter is incremented and no new DTCs are set, repair is successful and complete. Erase DTCs. See «CLEARING CODES»(ref-670-S00787086812000031300000) .

ON-VEHICLE TESTING

VOLTAGE DROP TEST

Note. VOLTAGE DROP TEST determines amount of resistance in circuits between generator and battery.

1. Ensure battery is in condition and is fully charged. Clean battery terminals (if necessary). Using external voltmeter, connect positive lead to generator B+ terminal stud (not the nut). Connect voltmeter negative lead to positive battery post. Connect tachometer to engine. Fully engage parking brake, and place gear selector in Neutral position. Start engine and run for 2 minutes to allow for warm-up.
2. Turn A/C system on, A/C-heater blower motor to high speed and headlights on high beam. Increase engine speed to 2400 RPM. Voltmeter reading should not be more than 0.6 volts.
3. If voltage drop is more than 0.6 volts, inspect, clean and tighten all connections between generator B+ terminal and positive battery post. Voltage drop test may be performed at each connection to locate connection with excessive resistance. If resistance tests are satisfactory, reduce engine speed, turn off all electrical loads and ignition switch.
4. Using external voltmeter, connect positive lead to generator ground terminal stud (not the nut). Connect voltmeter negative lead to negative battery post. Connect tachometer to engine. Fully engage parking brake, and place gear selector in Neutral position. Start engine and run for 2 minutes to allow for warm-up.
5. Turn A/C system on, A/C-heater blower motor to high speed and headlights on high beam. Increase engine speed to 2400 RPM. Voltmeter reading should not be more than 0.3 volts.
6. If voltage drop is more than 0.3 volt, inspect, clean and tighten all connections between generator ground terminal and negative battery post. Voltage drop test may be performed at each connection to locate connection with excessive resistance. If resistance tests are satisfactory, reduce engine speed and turn off all electrical loads and ignition switch.

CURRENT OUTPUT TEST

Note. Perform VOLTAGE DROP TEST before continuing with this test. Perform test soon after starting engine, as charging amperage will drop quickly. A volt/amp tester equipped with both a battery load control (carbon pile rheostat) and an inductive type pick-up clamp is required to perform the following test.

1. Ensure battery is in good condition and is fully charged. Clean battery terminals (if necessary). Connect volt/amp tester leads to battery. Ensure carbon pile is in OFF position before connecting leads. Connect inductive pick-up clamp. NOTE: Depending on volt/amp tester manufacturer, load may be applied automatically. Refer to volt/amp tester manufacturer's instructions.
2. Connect tachometer to engine. Start engine and raise engine speed to 2500 RPM. Slowly adjust rheostat control (load) on volt/amp tester until highest amperage reading is obtained. DO NOT allow voltage to drop less than 12 volts.
3. Note reading on ammeter. Generator amperage reading should be more than the minimum amperage rating specification. See «GENERATOR SPECIFICATIONS»(ref-670-S42355081932000031300000) table. If amperage reading is less than minimum specification, go to step 5 . If amperage reading is more than minimum specification, go to next step.
4. Rotate load control knob to OFF position. Continue to hold engine speed at 2500 RPM. Output amperage should change to less than 20-amps, indicating EVR circuity is okay and charging system is functioning properly. It may take several minutes for amperage to change. If output amperage does not change to less than 20-amps, perform «SELF-DIAGNOSTIC SYSTEM»(ref-670-S35453991852000031300000) .
5. Connect a jumper wire between ground and generator field driver terminal (Dark Green wire) on back of generator. Start engine, and immediately reduce engine speed to idle. Adjust carbon pile and engine speed in increments until engine speed is 1250 RPM and voltmeter reads 15 volts. DO NOT allow voltage to exceed 16 volts.
6. Note reading on volt/amp tester. Generator amperage reading should be more than the minimum amperage rating specification. See «GENERATOR SPECIFICATIONS»(ref-670-S42355081932000031300000) . If amperage reading is less than minimum specification, replace generator. If amperage reading is more than minimum specification, a fault exists in EVR circuitry. Perform «SELF-DIAGNOSTIC SYSTEM»(ref-670-S35453991852000031300000) .

GENERATOR APPLICATION

OUTPUT VOLTAGE TEST

1. Before performing this test, ensure battery is fully charged. Connect voltmeter leads across battery terminals. Record voltage with ignition switch and all electrical loads off. Fully engage parking brake, and place gear selector in Park position.
2. Start engine and operate at normal operating temperature. Record voltage with engine speed at 1500 RPM and no electrical loads. Voltage should not be greater than voltage recorded in step 1 by more than 2.5 volts. If voltage is not as specified, go to «SELF-DIAGNOSTIC SYSTEM»(ref-670-S35453991852000031300000) .
3. Record voltage with engine speed at 2000 RPM, blower motor on high and headlights on high beam. Voltage should be more than 0.5 volt above battery voltage previously recorded in step 1 . If voltage is less than 0.5 volt above previously recorded battery voltage, go to «SELF-DIAGNOSTIC SYSTEM»(ref-670-S35453991852000031300000) . If voltage tests are satisfactory, reduce engine speed, and turn off blower motor, headlights and ignition switch.

BENCH TESTING

Note. Generator is not serviceable. Replace generator if defective.