Radio

B143B-MICROPHONE 1 CIRCUIT LOW





For a complete wiring diagram, refer to the Wiring Information.

- When Monitored:
With the ignition on.

- Set Condition:
The Radio detects a short to ground or open on the (X712) Microphone 1 IN (+) circuit.





1. CHECK FOR ACTIVE DTC

NOTE: Verify the connection of the Inside Rearview Mirror harness connector.

1. Turn the ignition on.
2. With the scan tool, read the active DTCs.

Does the scan tool display B143B-MICROPHONE 1 CIRCUIT LOW as active?

Yes

- Go To 2

No

- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

2. CHECK FOR ACTIVE DTC B143E
1. With the scan tool, read the active DTCs.

Does the scan tool display B143E-MICROPHONE 2 CIRCUIT LOW also as active?

Yes

- Go To 3

No

- Go To 6

3. CHECK FOR VOLTAGE AT THE INSIDE REARVIEW MIRROR




1. Turn the ignition off.
2. Disconnect the Inside Rearview Mirror harness connector.
3. Turn the ignition on.
4. Measure the voltage between the (X793) Microphone Feed circuit and ground.

Is the voltage above 10.0 volts?

Yes

- Go To 6

No

- Go To 4

4. CHECK FOR VOLTAGE AT THE RADIO




1. While back probing, measure the voltage between the (X793) Microphone Feed circuit and ground at the Radio C2 harness connector.

NOTE: The graphic shows the connector for reference only. Back probe the harness connector.

Is the voltage above 10.0 volts?

Yes

- Repair the (X793) Microphone Feed circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 5

5. RESTORE THE VEHICLE CONFIGURATION
1. With the scan tool, restore the vehicle configuration.
2. Turn the ignition off, then back on.
3. With the scan tool, read the active DTCs.

Does the scan tool display B143B-MICROPHONE 1 CIRCUIT LOW as active?

Yes

- Replace the Radio.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

6. CHECK THE INSIDE REARVIEW MIRROR




1. Turn the ignition off.
2. Disconnect the Inside Rearview Mirror C2 harness connector.
3. Connect a jumper wire between the (X793) Microphone Feed and the (X712) Microphone 1 IN (+) circuits.
4. Turn the ignition on.
5. With the scan tool, read the DTCs.

NOTE: DTC B143C-MICROPHONE 1 CIRCUIT HIGH should display as active as a result of this test.

Does the scan tool display B143B-MICROPHONE 1 CIRCUIT LOW as active?

Yes

- Go To 7

No

- Replace the Inside Rearview Mirror.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

7. CHECK FOR THE (X712) MICROPHONE 1 IN (+) CIRCUIT OPEN




1. Turn the ignition off.
2. Disconnect the Radio C2 harness connector.
3. Measure the resistance of the (X712) Microphone 1 IN (+) circuit between the Inside Rearview Mirror and Radio C2 harness connectors.

Is the resistance above 10K Ohms?

Yes

- Repair the (X712) Microphone 1 IN (+) circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 8

8. CHECK FOR THE (X712) MICROPHONE 1 IN (+) CIRCUIT SHORTED TO GROUND




1. Measure the resistance between ground and the (X712) Microphone 1 IN (+) circuit.

Is the resistance below 10K Ohms?

Yes

- Repair the (X712) Microphone 1 IN (+) circuit for short to ground.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Replace the Radio.
- Perform the BODY VERIFICATION TEST. Body Verification Test.