Inspection Procedure 2: Vehicle power does not turn ON. (not possible with both of power supply mode ACC and ON)

caution

Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.

COMMENTS ON TROUBLE SYMPTOM

When the vehicle power does not turn ON (not possible with both of power supply mode ACC and ON), the battery, CAN bus line, OSS-ECU, OSS-ECU power supply, or earth circuit may have a problem.

note

OSS-ECU can communicate with the M.U.T.-III even when the engine switch is in the "OFF" position.

PROBABLE CAUSES

Malfunction of battery
Damaged wiring harness and connectors
Malfunction of engine switch (poor connector contact, poor engine switch contact)
Malfunction of the CAN bus line
Malfunction of OSS-ECU
ETACS-ECU malfunction

DIAGNOSIS PROCEDURE

STEP 1. Battery check

Perform the battery test to check the battery status. (Refer to GROUP 54A - Battery

Q. Is the check result normal?

Go to Step 2.

Replace the battery.

STEP 2. Check that the M.U.T.-III communicates with this system.

Check that the communication with M.U.T.-III is possible.

note

If ETACS-ECU is not active, OSS-ECU cannot communicate with the M.U.T.-III.

(1)Perform the ON/OFF operation of any of the door switches for several times, or open any of the doors.

(2)Check that OSS-ECU can communicate with the M.U.T.-III.

Q. Is the check result normal?

Go to Step 3.

Carry out the troubleshooting of "OSS-ECU power supply or earth circuit malfunction".(Refer to

STEP 3. M.U.T.-III CAN bus diagnostics

Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?

Go to Step 4.

Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting

STEP 4. M.U.T.-III diagnosis code

Check if the diagnosis code is set to OSS-ECU.

Q. Is the diagnosis code set?

Diagnose the OSS. Refer to

Go to Step 5.

STEP 5. Engine switch check

Continuity check of engine switch (Refer to

Q. Is the check result normal?

Go to Step 6.

Replace the engine switch.

STEP 6. Check of the troubles

Check that the vehicle power can be turned ON.

Q. Is the check result normal?

Intermittent malfunction is suspected (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction

Carry out the troubleshooting relevant to the input signal of ETACS-ECU. (Refer to GROUP 54A - ETACS

.) Then, go to Step 7.

STEP 7. Check of the troubles

Check that the vehicle power can be turned ON.

Q. Is the check result normal?

This diagnosis is complete.

Replace the OSS-ECU and register the chassis number (Refer to