P2504 CHARGING SYSTEM OUTPUT HIGH

When Monitored and Set Condition:

When Monitored: While the engine is running.
Set Condition: Battery voltage is less than 11.5 volts for more than 8 seconds. Battery voltage must exceed 12 volts for more than 5 seconds for fault to become inactive.

POSSIBLE CAUSES

• OTHER DTC'S PRESENT
• DIRTY OR LOOSE CONNECTIONS
• ADD-ON OR ACCESSORY WIRES AT BATTERY TERMINAL
• HIGH RESISTANCE IN THE B+ CIRCUIT
• HIGH RESISTANCE IN THE B+ CROSS OVER CABLE
• HIGH RESISTANCE IN THE GROUND CIRCUIT
• GENERATOR
• ECM
• INTERMITTENT CONDITION

DIAGNOSTIC PROCEDURE

NOTE: Refer to VERIFICATION TESTS for appropriate verification test procedures.

1. With the DRBIII®, read DTCs. Is DTC P2502 set?
   Yes --> Repair other DTCs first. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
   No --> Go To 2
2. Visually inspect the positive and negative connections at the battery. Visually inspect the battery negative connections at the engine block. Are the connections free of corrosion and are they tight?
   Yes --> Go To 3
   No --> Clean and/or tighten the connections. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
3. 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 POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
   No --> Go To 4
4. 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 .4 volts?
   Yes --> Repair the high resistance in the B+ circuit from battery to the generator. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
   No --> Go To 5
5. 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 .4 volts?
   Yes --> Repair the high resistance in the B+ cross over cable from right side battery to left side battery. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
   No --> Go To 6
6. Measure the voltage between the generator case and the B- post of the battery. Is the voltage above .1 volts?
   Yes --> Repair the high resistance in the ground circuit. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
   No --> Go To 7
7. Disconnect the Generator field harness connector.
   NOTE: Check connectors - Clean/repair as necessary.
   Measure the resistance between the generator field terminals at the generator. Is the resistance between .5 and 15 Ohms?
   Yes --> Go To 8
   No --> Replace the generator. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
8. Measure and record the voltage between battery positive circuit of the ECM harness connector and the battery negative circuits of the ECM harness connector. Reconnect the ECM connectors. Use the DRBIII® to measure and record battery voltage. Compare the voltage reading from the voltmeter with that of the DRBIII®. Are the readings within 3 volts of each other?
   Yes --> Refer to the SYMPTOM: INTERMITTENT CONDITION Symptom (Diagnostic Procedure). Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
   No --> Replace and program the ECM in accordance with the Service Information. Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).