Compass Malfunction

Compass 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

This compass module is only used on vehicles without OnStar. The compass module communicates with the body control module (BCM) through the local interconnect network 3 (LIN) data circuit. The instrument panel cluster (IPC) receives compass information from the BCM via the serial data circuit. The IPC displays compass information in the driver information center (DIC).

Diagnostic Aids

* Check for aftermarket equipment installed or personal items that could create a magnetic field that could affect the performance of the compass.
* Cycle the ignition before performing the compass magnetic variation adjustment procedure.
* Check that the compass module is properly installed in the vehicle. The embossed arrow on the top of the module should be parallel with the centerline of the vehicle.

Reference Information
Schematic Reference

Instrument Cluster Schematics (Instrument Cluster Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Driver Information Center (DIC) Description and Operation (Driver Information Center (DIC))
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 (Programming and Relearning)for scan tool information

Circuit/System Verification

Ignition ON, compass ON, verify that there is a correct compass reading on the DIC.

If the compass is incorrect, refer to Compass Display Is Incorrect.
If the compass shows CAL or C, refer to Compass Displays CAL.
If the compass displays "- -" (dashes), refer to Compass Display Is Blank.

Circuit/System Testing

Perform the Compass Calibration and Magnetic Variance (Compass Calibration and Magnetic Variance).

If the compass is still incorrect, replace the K18 compass module.

Repair Instructions

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

Control Module References (Programming and Relearning)for compass module replacement, setup, and programming