PRE-RELEASE
DTC B2455
| DTC B2455 |
| 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 B2455 02
Cellular Phone Microphone Circuit Short to Ground
DTC B2455 04
Cellular Phone Microphone Circuit Open
| Diagnostic Fault Information |
| Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
| Cellular Microphone Signal | B2455 02 | B2455 04 | - | - |
| Cellular Microphone Low Reference | - | B2455 04 | 1 | - |
| 1. OnStar Microphone Inoperative - Caller Cannot Be Heard | ||||
| Circuit/System Description |
The telematics communication interface control module provides the cellular phone microphone with a supplied voltage on the cellular phone microphone signal circuit. When the microphone is in use, voice data from the user is sent back to the telematics communication interface control module on the signal circuit. The telematics communication interface control module provides a ground for the cellular phone microphone via the low reference wire.
| Conditions for Running the DTC |
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The ignition must be in the RUN or ACC position.
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The system voltage is at least 9.5 V and no more than 15.5 V.
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All the above conditions are present for greater than 10 seconds.
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| Conditions for Setting the DTC |
B2455 02
The telematics communication interface control module detects an short to ground in the cellular phone microphone signal circuit for 10 seconds or greater.B2455 04
The following conditions will set this DTC:| • |
The telematics communication interface control module detects an open/high resistance in the cellular phone microphone signal circuit for 10 seconds or greater.
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The telematics communication interface control module detects an open/high resistance in the low reference circuit for 10 seconds or greater.
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| Action Taken When the DTC Sets |
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The OnStar® status LED turns red.
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The telematics communication interface control module will not receive a signal from the cellular phone microphone.
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Calls can be placed but the caller cannot be heard.
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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 B24 cellular phone microphone.
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| 2. |
Ignition ON, test for 9.5-10.5 V between the signal circuit terminal B and ground.
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| 3. |
If less than the specified range, test the circuit for a short to ground, shorted together, or an open/high resistance. If the circuit tests normal, replace the K73 telematics communication interface control module.
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If greater than the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
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Test for 9.5-10.5 V between the signal circuit terminal B and the low reference circuit terminal A.
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If less than the specified range, test the low reference circuit for a short to ground, shorted together, or an open/high resistance. If the circuit tests normal, replace the K73 telematics communication interface control module.
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If greater than the specified range, test the low reference circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
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If all circuit test normal, replace the B24 cellular phone microphone.
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Mobile Telephone Microphone Replacement
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Control Module References
for telematics communication interface control module replacement, setup, and programming
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