• | 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 provide an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Cellular Microphone Signal | B2455 00 | B2455 00 | B2455 00 | -- |
Cellular Microphone Drain | -- | B2455 00 | 1 | -- |
1. OnStar Microphone Inoperative - Caller Cannot Be Heard |
The communication interface module (CIM) 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 CIM on the signal circuit. The CIM provides a ground for the microphone via the drain wire.
• | 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. |
• | 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. |
• | The OnStar® status LED turns red. |
• | The CIM will not receive a signal from the microphone. |
• | Calls can be placed but the caller cannot be heard. |
• | The condition responsible for setting the DTC no longer exists. |
• | A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred. |
OnStar Description and Operation
Control Module References for scan tool information
⇒ | If greater than the specified range, test the circuit for an open/high resistance. |
⇒ | If greater than the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the CIM. |
⇒ | If less than the specified range, test the signal for a short to ground or an open/high resistance. If the circuit tests normal, replace the CIM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for CIM replacement, setup, and programming |