INSPECTION PROCEDURE A-2: Communication with the column switch (column-ECU) is not possible.


caution Whenever the ECU is replaced, ensure that the power supply circuit, the earthing circuit and the communication circuit are normal.


COMMENTS ON TROUBLE SYMPTOM
The power supply circuit to the column switch (column-ECU) may be defective. If the wiring harness of the battery power supply circuit for the ECU (column switch terminal No.1) is defective, also check the power supply circuit to the ignition switch (IG1) (column switch terminal No.9) and repair if necessary.

TROUBLESHOOTING HINTS

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

DIAGNOSIS PROCEDURE

Step 1. ECU check by using the SWS monitor
Check that the power supply and earth lines to the ETACS-ECU and the SWS communication lines are normal.

  • Ignition switch: OFF
ECUS TO BE CHECKED
  • ETACS ECU
OK: "OK" is displayed on the "ETACS ECU" menu.

Q. Is the check result normal?
Go to Step 2.
Refer to Inspection Procedure A-3 "Communication with the ETACS-ECU is not possible ."

Step 2. Connector check: C-301 column switch connector

Q. Is the check result normal?

Go to Step 3.

Repair the defective connector.

Step 3. Voltage measurement at the C-301 column switch connector.

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Voltage between C-301 column switch connector No.1 and body earth
OK: System voltage

Q. Is the check result normal?

Go to Step 5.

Go to Step 4.

Step 4. Check the wiring harness between C-301 column switch connector terminal No.1 to fusible link (26).


note Prior to the wiring harness inspection, check intermediate connectors C-125, and repair if necessary.

  • Check the power supply line for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

Step 5. Resistance measurement at the C-301 column switch connector.

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Continuity between C-301 column switch connector No.4 and body earth
OK: 2 Ω or less

Q. Is the check result normal?

Go to Step 7.

Go to Step 6.

Step 6. Check the wiring harness between C-301 column switch connector No.4 to body earth


  • Check the earth wires for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

Step 7. Connector check: C-221 ETACS-ECU connector

Q. Is the check result normal?

Go to Step 8.

Repair the defective connector.

Step 8. Check the wiring harness from C-221 ETACS-ECU connector terminal Nos. 59 and 68 to C-301 column switch connector terminal Nos. 3 and 2.



note Prior to the wiring harness inspection, check joint connector C-01, and repair if necessary.

  • Check the communication lines for open circuit.

Q. Is the check result normal?

Go to Step 9.

Repair the wiring harness.

Step 9. ECU check by using the SWS monitor

  • Ignition switch: OFF
ECUS TO BE CHECKED
  • COLUMN ECU
OK: "OK" is displayed on the "COLUMN ECU" menu.

Q. Is the check result normal?
Go to Step 10.
Replace the column switch.

Step 10. Retest the system.
Check that the ETACS-ECU communicates with the column switch.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Replace the ETACS-ECU.