Inspection Procedure 1: The ignition switch (ACC) signal is not received.


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






COMMENTS ON TROUBLE SYMPTOM



PROBABLE CAUSES



  • Malfunction of the ETACS-ECU
  • Malfunction of the ignition switch
  • Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-317 ETACS-ECU connector

Q. Is the check result normal?
Go to Step 2.
Repair the defective connector.

STEP 2. Voltage measurement at the C-317 ETACS-ECU connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Turn the ignition switch to the ACC position.
(3)Measure the voltage between the C-317 ETACS-ECU connector terminal No. 7 and the body earth.
OK: System voltage

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

STEP 3. Wiring harness check between the C-317 ETACS-ECU connector terminal No. 7 and the ignition switch (ACC)

  • Check the power supply (ACC) line for open circuit.

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 wiring harness.

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

  • Turn the ignition switch to the ACC position.
Item No.
 Item name
 Normal condition
Item 288
 ACC switch
 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 ETACS-ECU.