B1492

B1492-GENERAL MICROPHONE PERFORMANCE

B1492 - General Microphone Performance:

WHEN MONITORED
With the ignition on.

SET CONDITION
The Hands Free Module detects a fault in any of the microphone circuits.

POSSIBLE CAUSES
- (X712) Microphone 1 in (+) circuit open
- (X722) Microphone 2 in (+) circuit open
- (X792) Microphone in (-) circuit open
- (X712) (X722) (X792) Microphone circuits shorted to ground
- (X712) (X722) (X792) Microphone circuits shorted to voltage
- (X712) (X722) (X792) Microphone circuits shorted together
- Inside rear view mirror
- Hands free module

Diagnostic Test

1. CHECK FOR ACTIVE DTC

With the scan tool, read the active DTC's.
Cycle the ignition switch from off to on at least 5 times, leaving the ignition on for a minimum of 90 seconds per cycle.
Attempt to make a phone call with the system.
With the scan tool, read the active DTC's.

Q: Does the scan tool display this DTC as active?

YES: Go To 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.




2. (X712) MICROPHONE 1 IN (+) CIRCUIT OPEN

Turn the ignition off.
Disconnect the Hands Free Module harness connector.
Disconnect the Inside Rear View Mirror C2 harness connector.
Measure the resistance of the (X712) Microphone 1 IN (+) circuit between the HFM connector and the inside rear view mirror connector.

Q: Is the resistance below 5.0 ohms?

YES: Go To 3
NO: Repair the (X712) Microphone 1 IN (+) circuit for an open. Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test




3. (X722) MICROPHONE 2 IN (+) CIRCUIT OPEN

Measure the resistance of the (X722) Microphone 2 IN (+) circuit between the HFM connector and the inside rear view mirror connector.

Q: Is the resistance below 5.0 ohms?

YES: Go To 4
NO: Repair the (X722) Microphone 2 IN (+) circuit for an open. Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test




4. (X792) MICROPHONE IN (-) CIRCUIT OPEN

Measure the resistance of the (X792) Microphone IN (-) circuit between the HFM connector and the inside rear view mirror connector.

Q: Is the resistance below 5.0 ohms?

YES: Go To 5
NO: Repair the (X792) Microphone IN (-) circuit for an open. Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test




5. (X712) (X722) (X792) MICROPHONE CIRCUITS SHORTED TO GROUND

Measure the resistance between ground and each (X712) (X722) (X792) Microphone circuit.

Q: Is the resistance below 100.0 ohms?

YES: Repair the Microphone circuit that measured below 100.0 ohms for short to ground. Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 6




6. (X712) (X722) (X792) MICROPHONE CIRCUITS SHORTED TO VOLTAGE

Turn the ignition on.
Measure the voltage of each (X712) (X722) (X792) Microphone circuit.

Q: Is the voltage above 1.0 volt?

YES: Repair the Microphone circuit that measured above 1.0 volt for short to voltage. Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 7




7. (X712) (X722) (X792) MICROPHONE CIRCUITS SHORTED TOGETHER

Turn the ignition off.
Measure the resistance between each (X712) (X722) (X792) Microphone circuit.

Q: Is the resistance below 100.0 ohms?

YES: Repair the Microphone circuit that measured below 100.0 ohms for a short together. Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 8

8. INSIDE REAR VIEW MIRROR

Replace the Inside Rear View Mirror.
Cycle the ignition switch from off to on at least 5 times, leaving the ignition on for a minimum of 90 seconds per cycle.
Attempt to make a phone call with the system.
With the scan tool, read the active DTC's.

Q: Does the scan tool display this DTC as active?

YES: Inspect the wiring and connectors for damage or shorted circuits. If ok, replace and program the Hands Free Module. Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Repair is complete. Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test