For 1990-2009 cars

## Compass Malfunction Mirror

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | 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 inside rearview mirror (ISRVM) uses 2 magnetic field sensors for compass direction. One sensor is for north and south, the other sensor is for east and west. As the vehicle travels with or against the earths magnetic pull, there will be a change in voltage on one or both sensors. As a result of the change in voltage, the ISRVM changes the heading on the compass display. The internal fault detection for the compass is handled by the ISRVM.

### Reference Information

#### Schematic Reference

Inside Rearview Mirror Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Driver Information Center (DIC) Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Ignition ON, compass ON, verify that there is a compass reading on the display.

⇒ | If the display is blank, replace the ISRVM.

⇒ | If the display shows the letter C or CAL, perform the compass calibration procedure. Refer to Compass Calibration and Magnetic Variance.

2. Verify that the compass reading on the display is correct.

⇒ | If not correct, perform the compass magnetic variation adjustment procedure. Refer to Compass Calibration and Magnetic Variance.

3. If the display is still incorrect, replace the ISRVM.

### Repair Instructions

Perform the Diagnostic Repair Verification

Control Module References for ISRVM replacement, setup and programming

## Compass Malfunction DIC

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Compass Voltage | 1 | 1 | -- | --
Compass LIN 3 | 1 | 1 | 1 | --
Compass Ground | -- | 1 | 1 | --
1. Compass Malfunction

### 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 top of the module should be parallel with the centerline of the vehicle.

### Reference Information

#### Schematic Reference

Instrument Cluster Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Driver Information Center (DIC) Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References 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

#### Compass Display Is Incorrect

1. Adjust or change the compass zone using the world magnetic variation map. Refer to Compass Calibration and Magnetic Variance.

⇒ | If the compass is still incorrect, perform the compass magnetic variation zone adjustment procedure. Refer to Compass Calibration and Magnetic Variance.

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

#### Compass Displays CAL

1. Perform the compass calibration procedure. Refer to Compass Calibration and Magnetic Variance.
2. If the compass still displays CAL or C, replace the compass module.

#### Compass Display Is Blank

1. Ignition OFF, disconnect the harness connector at the compass module.
2. Test for less than 5 ohm between the ground circuit terminal 2 and ground.

⇒ | If greater than the specified range, test the ground 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 after completing the diagnostic procedure.

Control Module References for compass module replacement, setup, and programming