On Star One or More Buttons Inoperative
On Star One or More Buttons Inoperative
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 On Star(R) button assembly consists of 3 buttons, Call/Answer, On Star(R) Call Center, and On Star(R) Emergency. The communication interface module (CIM) supplies the On Star(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.
Reference Information
Schematic Reference
On Star Schematics (On Star Schematics)
Connector End View Reference
Component Connector End Views (Connector Views)
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 On Star(R) Call Center first before pressing the emergency button in order to notify them of the test.
Ignition ON, press the On Star(R) Call buttons one at the time. Verify that all of the On Star(R) buttons operate normally.
If some On Star(R) buttons are inoperative but not all, replace the inside rearview mirror.
If none of the On Star(R) buttons operate, refer to circuit/system testing.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the On Star(R) button assembly.
2. Test for less than 5 Ohms between the button assembly ground circuit terminal E 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 B 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 600 K - 700 K Ohms between the keypad signal circuit terminal B 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 ground circuit for an open/high resistance. If the circuit tests normal, replace the CIM.
5. Ignition ON, test for 9.8-10.2 V between the keypad supply voltage circuit terminal A 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.
Component Testing
1. Ignition OFF, disconnect the harness connector at the button assembly.
2. Test for infinite resistance between the keypad supply voltage terminal A and the keypad signal terminal B.
• If less than the specified range, replace the button assembly.
3. Test for 1.4 K - 1.6 K Ohms between the keypad supply voltage terminal A and the keypad signal terminal B while pressing the black phone button.
• If not within the specified range, replace the button assembly.
4. Test for 2.7 K - 3.3 K Ohms between the keypad supply voltage terminal A and the keypad signal terminal B while pressing the blue On-Star(R) button.
• If not within the specified range, replace the button assembly.
5. Test for 2.7 K - 3.3 K Ohms between the keypad supply voltage terminal A and the keypad signal terminal B while pressing the red emergency button.
• If not within the specified range, replace the button assembly.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* On Star Button Assembly Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for CIM replacement, setup, and programming