P2503-CHARGING SYSTEM OUTPUT LOW

For a complete wiring diagram Refer to Section 8W.

When Monitored:
The engine running. The engine RPM is high enough to assure sufficient generator current output to satisfy the electrical loads.
Set Condition:
The battery sensed voltage is less than the target charging voltage, during engine operation, for a calibrateable amount of time. One Trip Fault. Generator light will illuminate.

EXCESSIVE RESISTANCE IN THE (A801) BATTERY POSITIVE CIRCUIT

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

Diagnostic Test

1. ACTIVE DTC

NOTE: Inspect the vehicle for aftermarket accessories that may exceed the Generator System output.

NOTE: The battery must be fully charged.

NOTE: The Generator belt tension and condition must be checked before continuing.

Ignition on, engine not running.
With a scan tool, select View DTCs and record the related Freeze Frame data.
With a scan tool, erase DTCs.
Start the engine.
Allow the idle to stabilize.
Ignition on, engine not running.
With the scan tool, select View DTCs.

Is the DTC Active at this time?

Yes

Go To 2

Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

2. FUSED B+ CIRCUIT HIGH RESISTANCE

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 can result in personal injury or death.

Ignition on, engine not running.
Measure the voltage between the Generator B+ Output Terminal and the Battery+ Post.
Start the engine.

Is the voltage above 0.4 of a volt?

Yes

Repair the excessive resistance in the battery positive circuit between the Generator and Battery.

Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Go To 3

3. GENERATOR OPERATION

Turn the ignition off.
Disconnect the Generator Field harness connector.
Using a 12-volt test light connected to ground, probe (K125) Generator Field Control circuit in the Generator Field harness connector.
Ignition on, engine not running.
With a scan tool, actuate the Generator Field Driver.

Does the test light illuminate brightly and flash on and off?

Yes

Replace the Generator.

Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Go To 4

4. PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?

Yes

Repair as necessary.

Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)