Auxiliary Gauges Malfunction

Auxiliary Gauges Malfunction

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.

Circuit/System Description

The Auxiliary Gauge Module contains four gauges that can display voltage, engine oil temperature, engine oil pressure, and either transmission fluid temperature or boost pressure based on the information from the Engine Control Module (ECM) or Transmission Control Module (TCM). The ECM reads the information from various sensors and sends the information via serial data to the Body Control Module (BCM). The BCM then sends the information via serial data to the Auxiliary Gauge Module to display the information.

Reference Information

Schematic Reference

Instrument Cluster Schematics Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views Fuel Pump and Level Sensor Assembly - Primary

Description and Operation

Auxiliary Gauges Description and Operation Auxiliary Gauges Description and Operation

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON, perform the Auxiliary Gauge Sweep test with the scan tool, verify all auxiliary gauges sweep from the low to high positions.

• If none of the auxiliary gauges sweep properly
Refer to Circuit/System Testing.

• If one, two, or three of the auxiliary gauges sweep properly
Replace the P26 Auxiliary Gauge Module.

• If all auxiliary gauges sweep properly

2. All OK.

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the P26 Auxiliary Gauge Module. It may take up to 2 minutes for all vehicle systems to power down.

2. Test for less than 10 ohms between the ground circuit terminal 2 and ground.

• If 10 ohms or greater

1. Ignition OFF.

2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, repair the open/high resistance in the ground connection.

• If less than 10 ohms

3. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.

• If the test lamp does not illuminate and the circuit fuse is OK

1. Test for less than 2 ohms in the B+ circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, verify the fuse is OK and there is voltage at the fuse.

• If the test lamp does not illuminate and the circuit fuse is open

1. Test for infinite resistance between the B+ circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance, replace the P26 Auxiliary Gauge Module.

• If the test lamp illuminates

4. Connect the harness connector at the P26 Auxiliary Gauge Module. Ignition ON.

5. Verify scan tool communicates with the Auxiliary Gauge Module.

• If scan tool does not communicate with the Auxiliary Gauge Module
Refer to Scan Tool Does Not Communicate with Low Speed GMLAN Device Scan Tool Does Not Communicate with Low Speed GMLAN Device.

• If scan tool communicates with the Auxiliary Gauge Module

6. Replace the P26 Auxiliary Gauge Module.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

Control Module References Control Module References for Auxiliary Gauge Module replacement, programming, and setup