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 Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC B2476 04
- Cellular Phone Select Service Switch Open
DTC B2476 59
- Cellular Phone Select Service Switch Protection Time-out
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 telematics communication interface control module supplies the OnStar(R) button assembly with 10 V via the 10 V reference 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 pressed.
Conditions for Running the DTC
* Ignition ON.
* Battery voltage must be between 9-16 V.
Conditions for Setting the DTC
B2476 04
The telematics communication interface control module detects an open/high resistance on the keypad supply voltage circuit.
B2482 and B2476 59
The telematics communication interface control module 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 telematics communication interface control module will set this DTC.
Action Taken When the DTC Sets
* The OnStar(R) status LED turns red.
* No calls can be placed.
* The telematics communication interface control module 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 A/C Compressor Clutch
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 References 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.
1. Ignition ON.
2. Verify that each button of the S51 telematics button assembly operates normally by pressing each button individually.
• If none of the buttons operate normally
Refer to Circuit/System testing
• If some, but not all, of the buttons operate normally
Test or replace the A10 inside rearview mirror
• If all of the buttons operate normally
3. All OK.
Circuit/System Testing
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the A10 inside rearview mirror. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 15 omhs between the ground circuit terminal 8 and ground.
• If 15 omhs or greater
1. Ignition OFF.
2. Test for less than 2 omhs in the ground circuit end to end.
• If 2 omhs or greater, repair the open/high resistance in the circuit.
• If less than 2 omhs, repair the open/high resistance in the ground connection.
• If less than 15 omhs
3. Ignition ON.
4. Test for 9.5-10.5 V between the 10 V reference circuit terminal 12 and ground.
• If less than 9.5 V
1. Ignition OFF, disconnect the harness connector at the K73 telematics communication interface control module.
2. Test for infinite resistance between the 10 V reference circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 omhs in the 10 V reference circuit end to end.
• If 2 omhs or greater, repair the open/high resistance in the circuit.
• If less than 2 omhs, replace the K73 telematics communication interface control module.
• If greater than 10.5 V
1. Ignition OFF, disconnect the harness connector at the K73 telematics communication interface control module, ignition ON.
2. Test for less than 1 V between the 10 V reference circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K73 telematics communication interface control module.
• If between 9.5-10.5 V
5. Ignition OFF.
6. Test for 500-900 ohms between the signal circuit terminal 12 and ground.
• If less than 500 ohms
1. Disconnect the X1 harness connector at the K73 telematics communication interface control module.
2. Test for infinite resistance between the signal circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K73 telematics communication interface control module.
• If greater than 900 ohms
1. Disconnect the X1 harness connector at the K73 telematics communication interface control module, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V
3. Ignition OFF.
4. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K73 telematics communication interface control module.
• If between 500-900 ohms
7. Test or replace the A10 inside rearview mirror.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Inside Rearview Mirror Replacement Inside Rearview Mirror Replacement
* Control Module References Control Module References for telematics communication interface control module replacement, programming and setup.