P2502
P2502-CHARGING SYSTEM OUTPUT VOLTAGE
- When Monitored:
The engine is running.
- Set Condition:
The battery sensed voltage is above the generator sensed voltage by a certain amount, while the generator field duty cycle request has reached the maximum clamp.
OR
The generator sensed voltage is above the battery sensed voltage by a certain amount, or the generator sensed voltage is below a certain threshold. This is a two trip fault. Generator light will illuminate.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
1. ACTIVE DTC
NOTE: Diagnose and repair any Battery Voltage High DTCs, Battery Voltage Low DTCs, and battery connections before continuing with this test.
NOTE: Inspect the vehicle for aftermarket accessories that may exceed the Generator System output.
NOTE: The battery must be fully charged.
NOTE: The Generator belt tension and condition must be checked before continuing.
1. Ignition on, engine not running.
2. With a scan tool, select View DTCs.
3. Read and record the related Freeze Frame data for P2503.
4. With a scan tool, erase DTCs.
5. Start the engine.
6. Allow the idle to stabilize.
7. Ignition on, engine not running.
8. With the scan tool, select View DTCs.
Is the DTC Active at this time?
Yes
- Go To 2
No
- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Checking for an Intermittent DTC
2. FUSED B+ CIRCUIT HIGH RESISTANCE
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
1. Ignition on, engine not running.
2. Measure the voltage between the Generator B+ Output Terminal and the Battery + Post.
3. Start the engine.
Is the voltage above 0.4 of a volt?
Yes
- Repair the excessive resistance in the battery positive circuit between the Generator and Battery.
- Perform the PCM Verification Test. PCM Verification Test
No
- Go To 3
3. GENERATOR OPERATION
1. Turn the ignition off.
2. Disconnect the Generator Field harness connector.
3. Using a 12-volt test light connected to ground, probe (K20) Generator Field Control circuit in the Generator Field harness connector.
NOTE: The DTC needs to be cleared before actuating the Solenoid, if the DTC is not cleared, the Solenoid may not be allowed to actuate.
4. Ignition on, engine not running.
5. With a scan tool, actuate the Generator Field Driver.
Does the test light illuminate brightly and flash on and off?
Yes
- Replace the Generator.
- Perform the PCM Verification Test. PCM Verification Test
No
- Go To 4
4. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Generator and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals due to water intrusion.
4. Verify that there is good pin to terminal contact in the Generator, Battery, and Powertrain Control Module connectors.
5. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
6. Look for the data to change or for a DTC to set during the wiggle test.
7. Search for any Technical Service Bulletins that may apply.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the PCM Verification Test. PCM Verification Test
No
- Replace and program the Powertrain Control Module.
- Perform the PCM Verification Test. PCM Verification Test