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DTC B2476 Or B2482
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides 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 Short to Ground Open/High Resistance Short to Voltage Signal Performance
10 V Reference - B2476 04 - -
Control Terminal 6 1 1 2 -
Control Terminal 7 1 1 2 -
Control Terminal 3 3 3 - B2476 59, B2482 00
Ground - 1 - -
1. OnStar® LED Inoperative
2. LED Illuminated At All Times
3. OnStar® Buttons Inoperative
Circuit/System Description
The OnStar® button assembly consists of 3 buttons, Call/Answer, OnStar® Call Center, and OnStar®
Emergency. The communication interface module (CIM) supplies the OnStar® 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
YMMS: Feb 18, 2021
Engine: 3.6L Eng License:
VIN: Odometer:
2010 Chevrolet Camaro LT
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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® buttons is held or stuck for 15 seconds or greater, the CIM will set this DTC.
Action Taken When The DTC Sets
The OnStar® status LED turns red.
No calls can be placed.
The CIM will ignore all inputs from the OnStar® 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
Connector End View Reference
Component Connector End Views
Description and Operation
OnStar Description and Operation
Electrical Information Reference
Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs
Scan Tool Reference
Control Module References for 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 Ω between the mirror ground circuit terminal 5 and ground.
1. 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 3 and ground.
1. 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-800 k Ω between the keypad signal circuit terminal 3 and ground.
1. If less than the specified range, test the keypad signal circuit for a short to ground. If the circuit
tests normal, replace the CIM.
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2. 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 4 and ground.
1. 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.
2. 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 Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Inside Rearview Mirror Replacement
Control Module References for CIM replacement, setup, and programming
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