Inspection Procedure 1: 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.

PROBABLE CAUSES

  • Malfunction of the ETACS-ECU
  • Malfunction of the lighting 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 2 "Communication with the ETACS-ECU is not possible ."

STEP 2. Connector check: D-311 column switch connector

Q. Is the check result normal?
Go to Step 3.
Repair the defective connector.

STEP 3. Voltage measurement at D-311 column switch connector.
(1)Remove the column switch connector, and measure at the wiring harness side.
(2)Voltage between D-311 column switch connector terminal 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 D-311 column switch connector terminal No.1 and the fusible link (1).
note Prior to the wiring harness inspection, check intermediate connector D-241, 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 use troubleshooting/Inspection Service Points ).
Repair the wiring harness.

STEP 5. Voltage measurement at D-311 column switch connector.
(1)Remove the column switch connector, and measure at the wiring harness side.
(2)Ignition switch: ON
(3)Voltage between D-311 column switch connector terminal No.9 and body earth
OK: System voltage

Q. Is the check result normal?
Go to Step 7.
Go to Step 6.

STEP 6. Check the wiring harness between D-311 column switch connector terminal No.9 and the ignition switch (IG1).
note Prior to the wiring harness inspection, check junction block connectors D-403 and D-405, 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 use troubleshooting/Inspection Service Points ).
Repair the wiring harness.

STEP 7. Resistance measurement at the D-311 column switch connector.
(1)Remove the column switch, and measure at the wiring harness side.
(2)Resistance between D-311 column switch connector terminal No.4 and body earth
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?
Go to Step 9.
Go to Step 8.

STEP 8. Check the wiring harness between D-311 column switch connector terminal No.4 and 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 use troubleshooting/Inspection Service Points ).
Repair the wiring harness.

STEP 9. Connector check: D-420 ETACS-ECU connector

Q. Is the check result normal?
Go to Step 10.
Repair the defective connector.

STEP 10. Check the wiring harness from D-420 ETACS-ECU connector terminal Nos.59 and 68 to D-311 column switch connector terminal Nos.3 and 2.

  • Check the communication lines for open and short circuit.

Q. Is the check result normal?
Go to Step 11.
Repair the wiring harness.

STEP 11. 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 12.
Replace the lighting switch.

STEP 12. 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 use troubleshooting/Inspection Service Points ).
Replace the ETACS-ECU.