OnStar One or More Buttons Inoperative
OnStar One or More Buttons Inoperative
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)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 vehicle communication interface module (VCIM) supplies the OnStar(R) button assembly with 10 volts via the keypad 10 volt reference circuit . Each of the buttons, when pressed, completes the circuit across a resistor allowing a specific voltage to be returned to the VCIM over the keypad signal circuit. Depending upon the voltage range returned, the VCIM 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 Views)
Description and Operation
OnStar Description and Operation (OnStar Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
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 one or more, but not all, OnStar(R) buttons are inoperative, replace the inside rearview mirror.
If all of the OnStar(R) buttons are inoperative, refer to OnStar Button Circuit Malfunction.
Circuit/System Testing
OnStar Button Circuit Malfunction
1. Ignition OFF, disconnect the harness connector at the inside rearview mirror.
2. Ignition ON, test for 9.8-10.2 volts between the 10 volt reference circuit terminal 12 and ground.
• If greater than the specified range, test the 10 volt reference circuit for a short to voltage. If the circuit tests normal, replace the VCIM.
• If less than the specified range, test the 10 volt reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the VCIM.
3. Test for 0 volts between the 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 VCIM.
4. Test for 9.8-10.2 volts between the 10 volt reference circuit terminal 12 and the 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 VCIM.
5. Ignition OFF, disconnect the X1 harness connector at the VCIM.
6. Test for infinite resistance between the signal circuit terminal 11 and ground.
• If less than the specified range, test the signal circuit for a short to ground.
7. If all circuits test normal, test or replace the inside rearview mirror.
Component Testing
1. Ignition OFF, disconnect the harness connector at the inside rearview mirror .
2. Test for infinite resistance between the supply voltage terminal 12 and the signal terminal 11.
• If not the specified value, replace the inside rearview mirror.
3. Test for 1.4k-1.6k ohms between the supply voltage terminal 12 and the signal terminal 11 while pressing the black Call/Answer button.
• If not within the specified range, replace the inside rearview mirror.
4. Test for 2.7k-3.3k ohms between the supply voltage terminal 12 and the 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 supply voltage terminal 12 and the 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 (Verification Tests) after completing the diagnostic procedure.
* Inside Rearview Mirror Replacement (Inside Rearview Mirror Replacement)
* Control Module References (Programming and Relearning)for VCIM replacement, setup, and programming