Dodge Ram Truck 1500-2500-3500. Manual — part 1132

P2502-CHARGING SYSTEM ERROR (CONTINUED)

3.

HIGH RESISTANCE IN THE B+ CROSS OVER CABLE

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). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)

No

>> Go To 4

4.

HIGH RESISTANCE IN THE GROUND CIRCUIT

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). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)

No

>> Go To 5

5.

GENERATOR

Disconnect the Generator field harness connector.

NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between the generator field terminals.

Is the resistance between .5 and 15 Ohms?

Yes

>> Go To 6

No

>> Replace the generator.

Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)

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ENGINE - ELECTRICAL DIAGNOSTICS - DIESEL

DR/DH

P2502-CHARGING SYSTEM ERROR (CONTINUED)

6.

All

Turn the ignition off.

Reconnect the Generator field harness connector.

Disconnect the ECM harness connectors.

NOTE: Check connectors - Clean/repair as necessary.
Ignition on, engine not running.

Measure and record the voltage between battery positive circuits of
the ECM harness connector and the battery negative circuits of the
ECM harness connector.

Turn the ignition off.

Reconnect the ECM harness connectors.

Start the engine.

Use the scan tool to measure and record battery voltage.

Compare the voltage reading from the voltmeter with that of the scan
tool.

Are the readings within 3 volts of each other?

Yes

>> Test Complete.

No

>> Replace and program the ECM in accordance with the Service Information.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)

DR/DH

ENGINE - ELECTRICAL DIAGNOSTICS - DIESEL

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P2503-CHARGING SYSTEM OUTPUT LOW

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ENGINE - ELECTRICAL DIAGNOSTICS - DIESEL

DR/DH

P2503-CHARGING SYSTEM OUTPUT LOW (CONTINUED)

For the Engine circuit diagram (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CON-
TROL MODULE - SCHEMATIC - ELECTRICAL)

For a complete wiring diagram Refer to Section 8W.

•

When Monitored:
While the engine is running.

•

Set Condition:
The battery voltage exceeds target voltage by more than a calibrated value.

Possible Causes

OTHER DTC’S PRESENT

GENERATOR

FIELD DRIVER CIRCUIT SHORTED TO GROUND

ECM

INTERMITTENT CONDITION

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)

Diagnostic Test

1.

OTHER DTC’S PRESENT

With the scan tool, read DTCs.

Is DTC P2502 set?

Yes

>> Repair other DTC’s first.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)

No

>> Go To 2

2.

GENERATOR

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 3

No

>> Replace the generator.

Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)

DR/DH

ENGINE - ELECTRICAL DIAGNOSTICS - DIESEL

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