P063A

P063A-GENERATOR VOLTAGE SENSE CIRCUIT

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. Pre-Diagnostic Troubleshooting Procedure.

Diagnostic Test

1. DTC IS ACTIVE
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. Intermittent Condition Test.

2. CHECK FOR THE (A804) GENERATOR SENSE CIRCUIT SHORTED TO ANOTHER VOLTAGE SUPPLY CIRCUIT
1. Turn the ignition off.
2. Disconnect the Generator harness connector.
3. Disconnect the PCM C2 harness connector.
4. Measure the resistance between the (A804) Generator Sense circuit and all other 5 volt and 12 volt circuits at the PCM C2 harness connector.

Is the resistance above 10k Ohms between the (A804) Generator Sense circuit and all other 5 volt and 12 volt circuits?

Yes

- Go To 3

No

- Repair the (A804) Generator Sense circuit for a short to circuit that measured below 1000 Ohms.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

3. CHECK THE (A804) GENERATOR SENSE CIRCUIT FOR A SHORT TO GROUND
1. 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 POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

4. CHECK THE (A804) GENERATOR SENSE CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (A804) Generator Sense circuit between the Generator harness connector and the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 5

No

- Repair the (A804) Generator Sense circuit for an open circuit or high resistance.
- Perform the POWERTRAIN 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.
2. Reconnect the Powertrain Control Module (PCM) C2 harness connector.
3. Turn the ignition on.
4. Back probing and measure the voltage of the (K20) Generator Field Control circuit in the Powertrain Control Module (PCM) harness connector.

CAUTION:
Use only approved back probe tools when back probing a connector so as not to cause damage to the terminals or insulation of the connector. Damage to the terminals can cause poor terminal contact or retention. Damage to the insulation can introduce corrosion due to water infiltration.

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. Service and Repair.
- Perform the POWERTRAIN 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 POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

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