• 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.

The radio provides the microphone 2 with a supplied voltage on the microphone high signal circuit. When the microphone is in use, voice data from the user is sent back to the radio on the microphone low signal circuit. This microphone is used for driver side hands free calling enhancement, as well as a reference microphone for the primary microphone.

• The ignition must be in the RUN or ACC position/vehicle in Service Mode.
• The system voltage is at least 9.5 V and no more than 15.5 V.
• All the above conditions are present for greater than 5 s.

The radio detects a short to ground in the microphone high signal circuit for 5 s or greater.

The following conditions will set this DTC:

• The radio detects an open/high resistance in the microphone high signal circuit for 10 s or greater.
• The radio detects an open/high resistance in the microphone low signal circuit for 10 s or greater.

• The radio will not receive a signal from the microphone.

• The condition responsible for setting the DTC no longer exists.
• A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Radio/Navigation System Schematics

Master Electrical Component List

Radio/Audio System Description and Operation

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Control Module References for scan tool information

1. Ignition OFF/vehicle OFF, disconnect the harness connector at the B24RF Mobile Telephone Microphone – Right Front, ignition ON/vehicle in Service Mode.
2. Test for 9-11 V between the signal circuit terminal B and ground.
• If less than 9 V
1. Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the A11 Radio.
2. Test for infinite resistance between the signal circuit and ground.
• If less than infinite resistance, repair the short to ground in the circuit.
• If infinite resistance
3. Test for less than 2 Ω in the signal circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the A11 Radio.
• If greater than 11 V
1. Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the A11 Radio .
2. Test for less than 1 V between the signal circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the A11 Radio .
• If between 9-11 V
3. Test for less than 1 V between the low reference circuit terminal A and ground.
• If greater than 1 V
1. Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the A11 Radio .
2. Test for less than 1 V between the low reference circuit and ground.
• If 1 V or greater, repair the short to voltage in the circuit.
• If less than 1 V, replace the A11 Radio
• If less than 1 V
4. Test for greater than 9 V between the signal circuit terminal B and the low reference circuit terminal A.
• If less than 9 V
1. Ignition OFF/vehicle OFF, disconnect the X1 harness connector at the A11 Radio.
2. Test for infinite resistance between the low reference circuit and ground.
• If less than infinite resistance, repair the short to ground in the circuit.
• If infinite resistance
3. Test for less than 2 Ω in the signal circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the A11 Radio.
• If greater than 9 V
5. Test or replace the B24RF Mobile Telephone Microphone – Right Front.

Perform the Diagnostic Repair Verification after completing the repair.

• Mobile Telephone Microphone Replacement
• Control Module References for telematics communication interface control module replacement, programming and setup.