Charge Indicator Malfunction

Charge Indicator Malfunction

Diagnostic Instructions

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

Circuit/System Description

The engine control module (ECM) uses the generator turn ON signal circuit to control the load of the generator on the engine. A high side driver in the ECM applies a voltage to the voltage regulator. This signals the voltage regulator to turn the field circuit ON and OFF. The ECM monitors the state of the generator turn ON signal circuit. The ECM should detect low voltage on the generator turn on signal circuit when the ignition is ON and the engine is OFF, or when the charging system malfunctions. With the engine running, the ECM should detect high voltage on the generator turn on signal circuit. The ECM performs key ON and RUN tests to determine the status of the generator turn on signal circuit. If a malfunction is detected the ECM will illuminate the charge indicator in the instrument panel cluster (IPC).

Circuit/System Verification

1. Ignition ON, verify that the charge indicator illuminates during the self test when the ignition is turned ON.

^ If the charge indicator does not illuminate, replace the IPC.

2. Ignition ON, engine running, increase the engine speed to 1,500 RPM.
3. Verify that the scan tool Battery Voltage parameter is between 12.8-15.5 volts for the body control module (BCM), the ECM, and the IPC.

^ If all of the Battery Voltage parameters are not within the specified range for all of the modules, refer to Charging System Test. Charging System Test

^ If the Battery Voltage parameter is not within the specified range for the BCM, refer to Body Control Module Voltage Out Of Range.

^ If the Battery Voltage parameter is not within the specified range for the ECM, refer to Engine Control Module Voltage Out Of Range.

^ If the Battery Voltage parameter is not within the specified range for the IPC, refer to Instrument Panel Cluster Voltage Out Of Range.

Circuit/System Testing

Body Control Module Voltage Out Of Range
1. Ignition OFF, disconnect the harness connectors X2, X3, and X4 at the body control module.
2. Ignition ON, verify that a test lamp illuminates between the following terminals and ground.

* X2 terminal 2
* X3 terminal 2
* X3 terminal 3
* X4 terminal 1
* X4 terminal 2
* X4 terminal 3
* X4 terminal 4

^ If the test lamp does not illuminate, repair the appropriate battery voltage circuit for an open/high resistance.

3. Ignition OFF, test for greater than 1.0 ohm of resistance between the following terminals and ground.

* X3 terminal 1
* X3 terminal 5

^ If less than 1.0 ohm, test the appropriate ground circuit for an open/high resistance.

4. If all circuits test normal, test or replace the BCM.

Engine Control Module Voltage Out Of Range
1. Ignition OFF, disconnect the harness connectors X1 and X2 at the engine control module.
2. Ignition ON, verify that a test lamp illuminates between the following terminals and ground.

* X1 terminal 1 (Diesel)
* X1 terminal 77 (Diesel)
* X1 terminal 20 (Gas)

^ If the test lamp does not illuminate, repair the appropriate battery voltage circuit for an open/high resistance.

3. Ignition OFF, test for greater than 1.0 ohm of resistance between the following terminals and ground.

* X2-2 (Diesel)
* X2-4 (Diesel)
* X2-6 (Diesel)
* X2-51 (Diesel)
* X2 terminal 73 (Gas)

^ If less than 1.0 ohm, test the ground circuit for an open/high resistance.

4. If all circuits test normal, test or replace the ECM.

Instrument Panel Cluster Voltage Out Of Range
1. Ignition OFF, disconnect the harness connectors at the instrument panel cluster.
2. Ignition ON, verify that a test lamp illuminates between terminal 20 and ground.

^ If the test lamp does not illuminate, repair the appropriate battery voltage circuit for an open/high resistance.

3. Ignition OFF, test for greater than 1.0 ohm of resistance between terminal 7 and ground.

^ If less than 1.0 ohm, test the ground circuit for an open/high resistance.

4. If all circuits test normal, test or replace the IPC.

Repair Instructions

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

Refer to Programming and Relearning. Programming and Relearning