Charging System: Testing and Inspection

Charging System Test

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

Reference Information
Description and Operation

Charging System Description and Operation (Description and Operation)
Electrical Information Reference

Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)

Circuit/System Verification

Engine ON, observe the charge indicator on the instrument panel cluster (IPC) or message in the driver information center (DIC). The charge indicator on the IPC should be turned OFF and the DIC should not display charging system message.

If the charge indicator is not on the IPC or a charging system message is not displayed on the DIC, refer to Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections).

If the charge indicator is on the IPC or a charging system message is displayed on the DIC, refer to Circuit/System Testing.

Circuit/System Testing

1. Verify that a test lamp illuminates between the generator B+ and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. (NOTE) some vehicles use a maxi fuse or a fuseable link for this circuit, this circuit must be tested before diagnosing any charging system issues.

2. Ignition ON, verify that no generator or battery current sensor DTCs are set that would cause a charging system concern.

• If DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle).

3. Ignition OFF, measure the voltage across the battery terminals. The voltage should read 12.0 V or greater at room temperature.

• If not within specified value, refer to Battery Inspection/Test (Battery Inspection/Test).

4. Connect a carbon pile tester to the battery.
5. Start the engine and increase the engine speed to 2,500 RPM. Observe the voltage reading on the tester. The voltage should read between 12.6-15.0 V.

• If not within specified range, replace the generator.

6. Adjust the carbon pile tester to the specified load test output value, refer to Generator Usage (Specifications).

• If not within specified value, replace the generator.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

Generator Replacement (With 4.2L Engine) (Generator Replacement)Generator Replacement (5.3L Engine) (Generator Replacement)