DTC B1277 RHD
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 Descriptor
DTC B1277: Microphone CircuitDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Cellular Microphone Signal | B1277 02 | B1277 04 | B1277 01 | -- |
Cellular Microphone Drain | -- | B1277 04 | 1 | -- |
1. Microphone Inoperative - Caller Cannot Be Heard | ||||
Circuit/System Description
The communication interface module provides the cellular microphone with a supplied voltage on the cellular microphone signal circuit. When the microphone is in use, voice data from the user is sent back to the communication interface module on the signal circuit. The communication interface module provides a ground for the microphone via the drain wire.
Conditions for Running the DTC
| • | The ignition must be in the RUN or ACC position. |
| • | The system voltage is at least 9.5 volts and no more than 15.5 volts. |
| • | All the above conditions are present for greater than 10 seconds. |
Conditions for Setting the DTC
| • | The CIM detects an open, short to ground or short to voltage in the cellular microphone signal circuit for 10 seconds or greater. |
| • | The CIM detects an open/high resistance in the drain wire circuit for 10 seconds or greater. |
Action Taken When the DTC Sets
| • | The communication interface module will not receive a signal from the microphone. |
| • | Calls can be placed but the caller cannot be heard. |
| • | The communication interface module commands the red LED ON. |
Conditions for Clearing the DTC
| • | The condition for setting the DTC is no longer present. |
| • | A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred. |
Reference Information
Schematic Reference
Radio/Navigation System Schematics
Connector End View Reference
Description and Operation
Radio/Audio System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the inside rearview mirror.
- Test for less than 10 Ω between the drain circuit terminal 2 and ground.
- Ignition ON, test for 9.5-10.5 V between the signal circuit terminal 10 and ground.
- If all circuit test normal, replace the cellular microphone.
| ⇒ | If greater than the specified range, test the circuit for an open/high resistance. |
| ⇒ | If less than the specified range, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the communication interface module. |
| ⇒ | If greater than the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the communication interface module. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for telematics module replacement, setup and programming. |
