P063A
P063A-GENERATOR VOLTAGE SENSE CIRCUIT
For a complete wiring diagram Refer to the Wiring Information.
- When Monitored:
The engine running. The engine speed greater than 1157 RPM.
- Set Condition:
The PCM recognizes the alternator output voltage is less than the Battery feed circuit voltage. One trip failure. The Generator light will illuminate. The fault will be checked again on the next key cycle.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
1. ACTIVE DTC
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. Start the engine.
4. Allow the idle to stabilize.
5. With the scan tool, View DTCs.
Is the DTC Active at this time?
Yes
- Go To 2
No
- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition Test.
2. EXCESSIVE RESISTANCE IN THE (A803) GENERATOR SENSE CIRCUIT
1. Turn the ignition off.
2. Disconnect the Generator harness connector.
3. Disconnect the C1 PCM harness connector.
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install PCM Pinout Box 8815 to perform diagnosis.
4. Measure the resistance of the (A803) Generator Sense circuit from the Generator harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
- Go To 3
No
- Repair the excessive resistance in the (A803) Generator Sense circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
3. (A803) GENERATOR SENSE CIRCUIT SHORTED TO GROUND
1. Measure the resistance between ground and the (A803) Generator Sense circuit at the Generator harness connector.
Is the resistance below 100 ohms?
Yes
- Repair the short to ground in the (A803) Generator Sense circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 4
4. GENERATOR OPERATION
1. Connect the C1 PCM harness connector.
2. Ignition on, engine not running.
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.
3. Using a 12-volt test light connected to ground, probe the (K20) Generator Field Control circuit in the Generator Field harness connector.
4. With a scan tool, actuate the Generator Field Driver.
NOTE: The test light should be illuminated and bright proportional to the maximum duty cycle allowed by the scan tool. For example, if the scan tool allows 100% actuation, the brightness should be as bright as a direct connection to the battery. If the scan tool allows a maximum 25% actuation, the brightness should be 25% as bright as a direct connection to the battery.
Does the test light illuminate brightly and flash on and off?
Yes
- Verify that there is good pin to terminal contact in the Generator and Powertrain Control Module connectors. If OK, replace the Generator.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 5
5. 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. Verify that there is good pin to terminal contact in the Generator and Powertrain Control Module connectors.
4. Search for any Technical Service Bulletins that may apply.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.