OnStar Button Malfunction

OnStar Button 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 Instructionsprovides an overview of each diagnostic category.

Diagnostic Fault Information






Circuit/System Description

The OnStar(R) button assembly consists of 3 buttons, Call/Answer, OnStar(R) Call Center, and OnStar(R) Emergency. The communication interface module (CIM) supplies the OnStar(R) button assembly with 10 V via the keypad supply voltage circuit. Each of the buttons, when pressed, completes the circuit across a resistor allowing a specific voltage to be returned to the CIM over the keypad signal circuit. Depending upon the voltage range returned, the CIM is able to identify which button has been activated.

Reference Information
Schematic Reference

OnStar Schematics OnStar Schematics
Connector End View Reference

Component Connector End Views Connector End Views By Name
Description and Operation

OnStar Description and Operation OnStar
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 Relearningfor scan tool information

Circuit/System Verification

Note: Contact the OnStar(R) Call Center first before pressing the emergency button in order to notify them of the test.

Ignition ON, press the OnStar(R) Call buttons one at the time. Verify that all of the OnStar(R) buttons operate normally.

If some OnStar(R) buttons are inoperative but not all, replace the inside rearview mirror.
If none of the OnStar(R) buttons operate, refer to circuit/system testing.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the inside rearview mirror.
2. Test for less than 10 Ohms between the mirror ground circuit terminal 8 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, test for less than 1 V between the keypad signal circuit terminal 11 and ground.

• If greater than the specified range, test the keypad signal circuit for a short to voltage. If the circuit tests normal, replace the CIM.

4. Ignition OFF, test for 600k-800k Ohms between the keypad signal circuit terminal 11 and ground.

• If less than the specified range, test the keypad signal circuit for a short to ground. If the circuit tests normal, replace the CIM.
• If greater than the specified range, test the keypad signal circuit for an open/high resistance. If the circuit tests normal, replace the CIM.

5. Ignition ON, test for 9.5-10.5 V between the keypad supply voltage circuit terminal 12 and ground.

• If less than the specified range, test the supply voltage circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the CIM.
• If greater than the specified range, test the supply voltage circuit for a short to voltage. If the circuit tests normal, replace the CIM.

6. If all circuits test normal, test or replace the button assembly.

Repair Instructions

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

* Inside Rearview Mirror Replacement Inside Rearview Mirror Replacement
* Control Module References Programming and Relearningfor CIM replacement, setup, and programming