INSPECTION PROCEDURE 2: Transfer-ECU Ignition Switch Circuit Malfunction


caution
  • If there is any problem in the CAN bus lines, an incorrect trouble symptom may occur. Prior to this diagnosis, always diagnose the CAN bus lines.
  • Whenever the ECU is replaced, ensure that the CAN bus lines are normal.

SYMPTOMS


When turning the ignition switch to ON, the transfer-ECU receives system voltage from the ignition switch.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list
Use the transfer-ECU service data to check the signals related to the operation of ignition switch.

  • Turn the ignition switch to the "ON" position.
Item No.
 Item name
 Normal condition
42
 Ignition switch
 ON

  • Turn the rear ignition switch to the "OFF" position.
Item No.
 Item name
 Normal condition
42
 Ignition switch
 OFF
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 ).
NO. : Go to Step 2.

STEP 2. Voltage measurement at transfer-ECU connector (IG terminal).
(1)Ignition switch: ON
(2)Disconnect the connector, and measure at the wiring harness side.
(3)Check the voltage between the transfer-ECU connector (IG terminal) and body earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 4.
Go to Step 3.

STEP 3. Check of short to power supply, short to earth, and open circuit in IG line between ignition switch (IG1) <Vehicles without keyless operation system> or IG1 relay <Vehicles with keyless operation system> and transfer-ECU connector.

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 ).
Repair the connector(s) or wiring harness.

STEP 4. Retest the system
Check that the ignition switch functions work normally.

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 transfer-ECU (Refer to ).