General Microphone Fault
GENERAL MICROPHONE FAULT
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 rearview mirror
- Hands free module
DIAGNOSTIC TEST
1. CHECK FOR ACTIVE DTC
Turn the ignition on.
With the DRB, read and record the HFM DTC's and then erase the DTC's.
Attempt to make a phone call with the system.
With the DRB, read the HFM DTC's.
Q: Did this DTC reset?
YES: Go To 2
NO: The condition that set this DTC is no longer present. Using the wiring diagram/schematic as a guide, inspect the wiring for chafed, pierced, pinched, and partially broken wires and the wiring harness connectors for broken, bent, pushed out, and corroded terminals.
2. (X712) MICROPHONE 1 IN (+) CIRCUIT OPEN
Turn the ignition off.
Disconnect the Hands Free Module harness connector.
Disconnect the Inside Rearview Mirror C2 harness connector.
Measure the resistance of the (X712) Microphone 1 IN (+) circuit between the HFM connector and the Inside Rearview 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 BODY VERIFICATION TEST - VER 1.
3. (X722) MICROPHONE 2 IN (+) CIRCUIT OPEN
Measure the resistance of the (X722) Microphone 2 IN (+) circuit between the HFM connector and the Inside Rearview 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 BODY VERIFICATION TEST - VER 1.
4. (X792) MICROPHONE IN (-) CIRCUIT OPEN
Measure the resistance of the (X792) Microphone IN (-) circuit between the HFM connector and the Inside Rearview 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 BODY VERIFICATION TEST - VER 1.
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 BODY VERIFICATION TEST - VER 1.
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 BODY VERIFICATION TEST - VER 1.
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 BODY VERIFICATION TEST - VER 1.
NO: Go To 8
8. INSIDE REARVIEW MIRROR
Replace the Inside Rearview Mirror in accordance with the service information.
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 DRB, read the HFM DTC's.
Q: Did this DTC reset?
YES: Inspect the wiring and connectors for damage or shorted circuits. If Ok, replace and program the Hands Free Module in accordance with the service information. Perform BODY VERIFICATION TEST - VER 1.
NO: Repair is complete. Perform BODY VERIFICATION TEST - VER 1.