PRE-RELEASE
DTC B2476 or B2482
| DTC B2476 or B2482 |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| 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 |
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10V Reference
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B2476 04
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Signal Terminal 3
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3
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3
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B2476 59, B2482 00
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Control Terminal 6
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1
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1
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2
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-
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Control Terminal 7
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1
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1
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2
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-
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Ground
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B2476 04
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1. OnStar® LED Inoperative
2. LED Illuminated At All Times 3. OnStar® Buttons Inoperative |
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| Circuit/System Description |
The OnStar® button assembly consists of 3 buttons, Call/Answer, OnStar® Call Center, and OnStar® Emergency. The telematics communication interface control module supplies the OnStar® button assembly with 10 V via the Telematics 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 Telematics Button Assembly signal circuit. Depending upon the voltage range returned, the telematics communication interface control module is able to identify which button has been activated.
| Conditions for Running the DTC |
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Ignition ON
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Battery voltage must be between 9-16 V.
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| Conditions for Setting the DTC |
B2476 04
The telematics communication interface control module detects an open/high resistance on the Telematics Button Assembly supply voltage circuit.B2482 and B2476 59
The telematics communication interface control module detects a valid signal on the Telematics Button Assembly signal circuit for longer than 15 seconds. If one of the OnStar® 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 |
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The OnStar® status LED turns red.
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No calls can be placed.
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The telematics communication interface control module will ignore all inputs from the OnStar® button assembly.
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| Conditions for Clearing the DTC |
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The condition responsible for setting the DTC no longer exists.
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A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.
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| Reference Information |
Schematic Reference
OnStar Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
OnStar Description and Operation
Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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Scan Tool Reference
Control Module References for scan tool information
| Circuit/System Testing |
| 1. |
Ignition OFF, disconnect the harness connector at the inside rearview mirror.
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| 2. |
Test for less than 5 Ω between the mirror ground circuit terminal 5 and ground.
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| 3. |
If greater than the specified range, test the ground circuit for an open/high resistance.
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| 4. |
Ignition ON, test for less than 1 V between the S51 Telematics Button Assembly signal circuit terminal 3 and ground.
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| 5. |
If the value is greater than the specified range, check if there is a short-circuit to voltage in the S51 signal circuit of the Telematics keypad. If the circuit test result is normal, replace the K73 telematics communication interface control module.
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| 6. |
Ignition OFF, test for 450-850 kΩ between the S51 Telematics Button Assembly signal circuit terminal 3 and ground.
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| 7. |
If the value is less than the specified range, check if there is a short-circuit to ground in the S51 signal circuit of the Telematics keypad. If the circuit test result is normal, replace the K73 telematics communication interface control module.
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| 8. |
If the value is greater than the specified range, check if there is an open circuit/high resistance in the S51 signal circuit of the Telematics keypad. If the circuit test result is normal, replace the K73 telematics communication interface control module.
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| 9. |
Ignition ON, test for 9.5-10.5 V between the S51 Telematics Button Assembly supply voltage circuit terminal 4 and ground.
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| 10. |
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 K73 telematics communication interface control module.
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| 11. |
If greater than the specified range, test the supply voltage circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
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| 12. |
If all circuits test normal, test or replace the button assembly.
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Inside Rearview Mirror Replacement
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Control Module References
for telematics communication interface control module replacement, setup, and programming
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