Inspection procedure 1: The 2WD/4WD Switch Signal is not Received. <Vehicles with 4WD and 5M/T>

caution

Whenever the ECU is replaced, ensure that the input signal circuit is normal.

COMMENTS ON TROUBLE SYMPTOM

If there is an error to the 2WD/4WD switch input signal, the 2WD/4WD switch signal is no longer output to the communication line.

PROBABLE CAUSES

Malfunction of 4WD indicator-ECU
Malfunction of the gateway-ECU
Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

Check the input signals from the 4WD indicator-ECU.

Operate the transfer shift position.

Item No.	Item name	Normal condition
8	Indicator SW (Front tyre)	OFF to ON
9	Indicator SW (Rear tyre)	ON

OK: Normal condition is displayed.

Q. Is the check result normal?

Go to Step 3.

Go to Step 2.

STEP 2. Check the wiring harness between 4WD indicator-ECU connector and the gateway-ECU connector.

Check of short to power supply, short to earth, and open circuit between gateway-ECU connector and 4WD indicator-ECU

Q. Is the check result normal?

Go to Step 3.

Repair the connector(s) or wiring harness.

STEP 3. Check the 4WD indicator-ECU

Refer to GROUP 22A - 4WD indicator-ECU, Inspection

Q. Is the check result normal?

Go to Step 4.

Replace the 4WD indicator-ECU.

STEP 4. M.U.T.-III data list

Operate the transfer shift position.

Item No.	Item name	Normal condition
8	Indicator SW (Front tyre)	OFF to ON
9	Indicator SW (Rear tyre)	ON

OK: Normal condition is displayed.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction).

Replace the gateway-ECU.