P063A

P063A-GENERATOR VOLTAGE SENSE CIRCUIT

Special Tools:










For a complete wiring diagram, refer to the Wiring Information.

- When Monitored:
With the engine running and battery voltage greater than 10.4 volts.

- Set Condition:
The Powertrain Control Module (PCM) detects no change when attempting to regulate the generator output.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. PCM Pre-Diagnostic Troubleshooting Procedure.

Diagnostic Test

1. ACTIVE DTC
1. Start the engine and allow it to reach normal operating temperature.

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.

2. With the scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. PCM Intermittent Condition Test.

2. CHECK THE (A804) GENERATOR SENSE CIRCUIT FOR A SHORT TO VOLTAGE




1. Turn the ignition off.
2. Disconnect the Generator harness connector.
3. Disconnect the PCM C2 harness connector.
4. Turn the ignition on.
5. Measure the voltage of the (A804) Generator Sense circuit in the Generator harness connector.

Is there any voltage present?

Yes

- Repair the (A804) Generator Sense circuit for a short to voltage.
- Perform the PCM Verification Test. Powertrain Verification Test.

No

- Go To 3

3. CHECK THE (A804) GENERATOR SENSE CIRCUIT FOR A SHORT TO GROUND




1. Turn the ignition off.
2. Measure the resistance between ground and the (A804) Generator Sense circuit in the Generator harness connector.

Is the resistance above 10k Ohms?

Yes

- Go To 4

No

- Repair the (A804) Generator Sense circuit for a short to ground.
- Perform the PCM Verification Test. Powertrain Verification Test.

4. CHECK THE (A804) GENERATOR SENSE CIRCUIT FOR AN OPEN/HIGH RESISTANCE

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 the GPEC Diagnostic Adaptor to perform the diagnosis.

1. Connect the (10436).
2. Measure the resistance of the (A804) Generator Sense circuit between the Generator harness connector and the GPEC Adaptor.

Is the resistance below 5.0 Ohms?

Yes

- Go To 5

No

- Repair the (A804) Generator Sense circuit for an open or high resistance.
- Perform the PCM Verification Test. Powertrain Verification Test.

5. GENERATOR

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. Connect the Generator 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 the GPEC Diagnostic Adaptor to perform the diagnosis.

2. Connect the (10436) in line with the PCM C2 harness connector.
3. Turn the ignition on.
4. measure the voltage of the (K20) Generator Field Control circuit at the GPEC Adaptor.
5. Start the engine.
6. With the scan tool, perform the Generator Full Field test.
7. Monitor the voltage of the (K20) Generator Field Control circuit with the Generator Full Field test actuated.

NOTE: The voltage should increase more than 1.0 volt.

Does the voltage increase by at least 1.0 volt with the Generator Full Field Test on?

Yes

- Go To 6

No

- Replace the Generator.
- Perform the PCM Verification Test. Powertrain Verification Test.

6. 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.
4. Perform any Technical Service Bulletins that may apply.

Were any problems found?

Yes

- Repair as necessary.
- Perform the PCM Verification Test. Powertrain Verification Test.

No

- Replace and program the Powertrain Control Module (PCM).
- Perform the PCM Verification Test. Powertrain Verification Test.