OnStar One or More Buttons Inoperative
OnStar One or More Buttons Inoperative
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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/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 volts 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.
Circuit/System Verification
Important: 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. Ignition ON, test for 9.8-10.2 volts 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.
3. Test for 0 volt 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. Test for 9.8-10.2 volts between the keypad supply voltage circuit terminal 12 and the keypad signal circuit terminal 11.
• If less than the specified range, test the keypad signal circuit for an open/high resistance. If the circuit tests normal, replace the CIM.
5. Test for less than 5 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.
6. Ignition OFF, disconnect the CIM X1 connector. Test for infinite resistance 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.
7. If all circuits test normal, test or replace the button assembly.
Component Testing
1. Ignition OFF, disconnect the harness connector at the inside rearview mirror.
2. Test for infinite resistance between the keypad supply voltage terminal 12 and the keypad signal terminal 11.
• If less than the specified range, replace the inside rearview mirror.
3. Test for 1.4k-1.6k ohms between the keypad supply voltage terminal 12 and the keypad signal terminal 11 while pressing the black phone button.
• If not within the specified range, replace the inside rearview mirror.
4. Test for 2.7k-3.3k ohms between the keypad supply voltage terminal 12 and the keypad signal terminal 11 while pressing the blue On-Star(R) button.
• If not within the specified range, replace the inside rearview mirror.
5. Test for 11.7k-14.3k ohms between the keypad supply voltage terminal 12 and the keypad signal terminal 11 while pressing the red emergency button.
• If not within the specified range, replace the inside rearview mirror.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Inside Rearview Mirror Replacement