Inspection Procedure 4

Inspection Procedure 4: No DTC is set even when the AWD/LOCK Indicator Lights Flash.

COMMENTS ON TROUBLE SYMPTOM

- In case that the AWD/LOCK indicator flashes but no DTC is set, the AWD-ECU power supply circuit system or AWD-ECU may have a problem.

- If the AWD-ECU power supply voltage is approximately 6.5 V or less when the system is in operation (always), the CPU of AWD-ECU automatically shuts down. At this time, if the AWD control is in operation, it switches to the FWD control. AWD-ECU cannot set the DTC because the CPU shuts down. In addition, the combination meter determines the AWD-ECU timeout, and flashes both AWD and LOCK indicators.

PROBABLE CAUSES

- Damaged wiring harness and connectors

- AWD-ECU malfunction

DIAGNOSIS

Required Special Tools:

- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface

- MB991827: M.U.T.-III USB Cable

- MB991910: M.U.T.-III Main Harness A

STEP 1. Check if AWD/LOCK Indicator Lights flash simultaneously

(1)Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.

(2)Check that the AWD/LOCK indicator lights flash simultaneously when the drive mode selector is switched to 4WD (AWD) position, or LOCK position.

Q. Does the AWD/LOCK Indicator Lights flash simultaneously?

YES
- When the drive system fluid temperature warning display illuminates in the combination meter, cool down the electronic control coupling.

- When the drive system fluid temperature warning display does not illuminate in the combination meter, referring to "Inspection Procedure 1: Scan tool MB991958 cannot Communicate with the Electronic Control AWD System[ECU power supply circuit system check] ", perform the check Inspection Procedure 1.

NO Referring to the Inspection Chart for Trouble Symptoms, perform the check Symptom Chart.