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.
Diagnostic Fault Information
Circuit/System Description
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 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, refer to Compass Displays CAL.
If the compass displays "- -" (dashes) or is blank, refer to Compass Displays No Heading.
Circuit/System Testing
Compass Display Is Incorrect
1. Adjust or change the compass zone using the world magnetic variation map. Refer to Compass Calibration and Magnetic Variance (without OnStar Only) (Compass Calibration and Magnetic Variance (without OnStar Only)).
• If the compass is still incorrect, perform the compass magnetic variation adjustment procedure. Refer to Compass Calibration and Magnetic Variance (without OnStar Only) (Compass Calibration and Magnetic Variance (without OnStar Only)).
2. If the compass is still incorrect, replace the compass module.
Compass Displays CAL
1. Perform the compass magnetic variation adjustment procedure. Refer to Compass Calibration and Magnetic Variance (without OnStar Only) (Compass Calibration and Magnetic Variance (without OnStar Only)).
2. If the compass still displays CAL, replace the compass module.
Compass Displays No Heading
1. Ignition OFF, disconnect the harness connector at the compass module.
2. Test for less than 5 ohm between the low reference circuit terminal 2 and ground.
• If greater than the specified range, test the circuit for a short to voltage or an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the voltage circuit terminal 1 and ground.
• If the test lamp does not illuminate, repair the circuit for a short to ground or an open/high resistance.
4. Ignition OFF, test for greater than 1 ohm between the compass LIN 3 data circuit terminal 3 and ground.
• If less than the specified range, test the LIN 3 data circuit for a short to ground.
5. Ignition ON, verify that a test lamp does not illuminate between the compass LIN 3 data circuit terminal 3 and ground
• If the test lamp illuminates, test the LIN 3 data circuit for a short to voltage.
6. Ignition OFF, disconnect the X4 harness connector at the BCM.
7. Test for less than 1 ohm between the compass LIN 3 data circuit terminal 3 to the BCM terminal 6.
• If greater than the specified range, repair the LIN 3 data circuit for an open/high resistance.
8. If all circuits test normal, replace the 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