P2504

P2504-CHARGING SYSTEM OUTPUT HIGH

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

Theory of Operation

There are two communication lines between the Powertrain Control Module (PCM) and Generator. Based on sensed battery voltage, the PCM commands the alternator to charge the batteries to a desired voltage. The max voltage the PCM will command the Generator to charge is 14.75 Volts. The PCM then receives feedback from the alternator on the voltage level it is charging the batteries. The PCM will not light a MIL lamp for this fault.

- When Monitored:
While the engine is running.

- Set Condition:
Battery voltage is less than 11.5 Volts for more than eight seconds. Battery voltage must exceed 12 Volts for more than five seconds for fault to become inactive.





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

1. ACTIVE DTC
1. With the scan tool, read DTCs.

Is DTC P065A active

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test

2. CHECK FOR DIRTY OR LOOSE CONNECTIONS
1. Visually inspect the positive and negative connections at the battery.
2. Visually inspect the battery negative connections at the engine block.

Are the connections tight and free of corrosion?

Yes

- Go To 3

No

- Clean and/or tighten the connections.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

3. CHECK FOR ADD-ON OR ACCESSORY WIRES AT BATTERY TERMINAL
1. Check for add-on or accessory wiring at positive (+) terminal of the battery.

Are there any damaged wires at the battery?

Yes

- Remove defective or miss wired add-on or accessory wiring from battery.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 4

4. CHECK FOR HIGH RESISTANCE IN THE B+ CIRCUIT
1. Measure the voltage between the B+ post of the generator and the B+ post of the battery while the engine is running.

Is the voltage above 0.4 Volts?

Yes

- Repair the high resistance in the B+ circuit from battery to the generator.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 5

5. CHECK FOR HIGH RESISTANCE IN THE B+ CROSS OVER CABLE
1. Measure the voltage between the B+ post of the generator and the B+ post of the right side battery to the left side battery while the engine is running.

Is the voltage above 0.4 Volts?

Yes

- Repair the high resistance in the B+ cross over cable from right side battery to left side battery.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 6

6. CHECK FOR HIGH RESISTANCE IN THE GROUND CIRCUIT
1. Measure the voltage between the generator case and the B- post of the battery.

Is the voltage above 0.1 Volts?

Yes

- Repair the high resistance in the ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 7

7. GENERATOR
1. Turn the ignition off.
2. Disconnect the Generator field harness connector.

NOTE: Check connectors - Clean/repair as necessary.

3. Measure the resistance between the generator field terminals at the generator.

Is the resistance between 0.5 and 15.0 Ohms?

Yes

- Go To 8

No

- Replace the Generator.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

8. POWERTRAIN CONTROL MODULE (PCM)
1. Disconnect the PCM connectors.
2. Measure and record the voltage between battery positive circuit of the PCM harness connector and the battery negative circuits of the PCM harness connector.
3. Reconnect the PCM connectors.
4. Use the scan tool to measure and record battery voltage.
5. Compare the voltage reading from the voltmeter with that of the scan tool.

Are the readings within 3.0 Volts of each other?

Yes

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test

No

- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.