B2482
DTC B2476 or B2482
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.
DTC Descriptors
DTC B2476 04
- Cellular Phone Select Service Switch Open Circuit
DTC B2476 59
- Cellular Phone Select Service Switch Stuck Button
DTC B2482 00
- Cellular Phone Select Service Switch Range/Performance
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.
Conditions for Running the DTC
* Ignition ON.
* Battery voltage must be between 9-16 V.
Conditions for Setting the DTC
B2476 04
The CIM detects an open/high resistance on the keypad supply voltage circuit.
B2482 and B2476 59
The CIM detects a valid signal on the keypad signal circuit for longer than 15 seconds. If one of the OnStar(R) buttons is held or stuck for 15 seconds or greater, the CIM will set this DTC.
Action Taken When the DTC Sets
* The OnStar(R) status LED turns red.
* No calls can be placed.
* The CIM will ignore all inputs from the OnStar(R) button assembly.
Conditions for Clearing the DTC
* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.
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
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 Control Module Referencesfor scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the A10 inside rearview mirror.
2. Test for less than 10 Ohms between the mirror ground circuit terminal 5 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 Control Module Referencesfor CIM replacement, setup, and programming