Operation CHARM: Car repair manuals for everyone.

Radio






B143E - Microphone 2 Circuit Low






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 inside rearview mirror harness connector.

Turn the ignition ON.

With the scan tool, read the DTC's.

Does the scan tool display this DTC as active?

Yes

Go to Test Step 3.

No

Replace the inside rearview mirror..

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

Test Step 3 - Microphone 2 in (+) Circuit Short to Ground






Turn the ignition OFF.

Disconnect the radio C1 harness connector.

Measure the resistance between ground and the Microphone 2 in (+) circuit.

Is the resistance less than 10K ohms?

Yes

Repair the microphone 2 in (+) circuit for short to ground.

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

No

Replace the radio.

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