Radio

B143C - Microphone 1 Circuit High






For a complete wiring diagram, refer to.

• When Monitored: With the ignition on.

• Set Condition: The radio detects a fault in any of the microphone circuits.






Test Step 1 - Check for Active Dtc

• With the scan tool, read the active DTC's.

• Cycle the ignition switch from OFF to ON.

• Attempt to make a phone call with the system.

• With the scan tool, read the active DTC's.

Does the scan tool display this DTC as active?

Yes

• Go to Test Step 2.

No

• If the DTC is stored, check for an intermittent condition. Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.

Test Step 2 - Inside Rearview Mirror






• Turn the ignition OFF.

• Disconnect the rearview mirror harness connector.

• Turn the ignition ON.

• With the scan tool, read the active DTC's.

Does the scan tool display this DTC as active?

Yes

• Go to Test Step 3.

No

• Replace the rearview mirror.

• Perform the Body Verification Test. Refer to => Non-DTC Based Diagnostics. Body Interior

Test Step 3 - Microphone 1 in (+) Circuit Short to Voltage






• Turn the ignition OFF.

• Disconnect the radio C1 harness connector.

• Turn the ignition ON.

• Measure the voltage of the microphone 1 in (+) circuit.

Is voltage present?

Yes

• Repair the microphone 1 in (+) circuit for a short to voltage.

• Perform the Body Verification Test. Refer to => Non-DTC Based Diagnostics. Body Interior

No

• Go to Test Step 4.

Test Step 4 - Microphone 1 in (+) Circuit Open






• Turn the ignition OFF.

• Measure the resistance of the microphone 1 in (+) circuit between the radio C1 connector and the inside rearview mirror connector.

Is the resistance less than 5.0 ohms?

Yes

• Replace the radio.

• Perform the Body Verification Test. Refer to => Non-DTC Based Diagnostics. Body Interior

No

• Repair the microphone 1 in (+) circuit for an open.

• Perform the Body Verification Test. Refer to => Non-DTC Based Diagnostics. Body Interior