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 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 telematics communication interface control module 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 telematics communication interface control module over the keypad signal circuit. Depending upon the voltage range returned, the telematics communication interface control module 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 Sunshade - Left Front
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 Relearning for 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 A10 inside rearview mirror.
2. Test for less than 10 omhs between the appropriate ground circuit terminal listed below and ground:
* Terminal 5 (UVC+UYS/UYX/-UVC/UYS/UYX)
* Terminal 8 (UVC-UYS/UYX)
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Test for 500-900 omhs between the appropriate signal circuit terminal listed below and ground:
* Terminal 3 (UVC+UYS/UYX/-UVC/UYS/UYX)
* Terminal 11 (UVC-UYS/UYX)
• If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the K73 telematics communication interface control module.
• If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the K73 telematics communication interface control module.
4. Ignition ON, test for 8.5-10.5 V between the appropriate 10 V reference circuit terminal listed below and ground:
* Terminal 4 (UVC+UYS/UYX/-UVC/UYS/UYX)
* Terminal 12 (UVC-UYS/UYX)
• If less than the specified range, test the 10 V reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the K73 telematics communication interface control module.
• If greater than the specified range, test the 10 V reference circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
5. Test for less than 1 V between the signal circuit terminal list below and ground.
* Terminal 3 (UVC+UYS/UYX/-UVC/UYS/UYX)
* Terminal 11 (UVC-UYS/UYX)
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
6. If all circuits test normal, test or replace the A10 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 telematics communication interface control module replacement, programming and setup