INSPECTION PROCEDURE A-3: Communication with the ETACS-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
It is suspected that the power supply circuit to the ETACS-ECU is defective, or the wiring harness between the SWS monitor and the ETACS-ECU or their connector(s) is damaged. If the battery power supply circuit to the ECU (terminal No.20 of the ETACS-ECU) is damaged, also check the power supply circuit from the ignition switch (IG1) (terminal No.8 of the ETACS-ECU), and repair if necessary. If the earth circuit to the ECU (terminal No.3 of the ETACS-ECU) is defective, also check the earth circuit to the sensor (terminal No.56 of the ETACS-ECU), and repair if necessary.

TROUBLESHOOTING HINTS

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

DIAGNOSIS PROCEDURE

Step 1. Connector check: C-219 ETACS-ECU connector


Q. Is the check result normal?

Go to Step 2.

Repair the defective connector.

Step 2. Voltage measurement at the C-219 ETACS-ECU connector.


(1)Remove the ETACS-ECU, and measure at the junction block side.

(2)Voltage between C-219 ETACS-ECU connector terminal No.20 and body earth
OK: System voltage

Q. Is the check result normal?

Go to Step 4.

Go to Step 3.

Step 3. Check the wiring harness between C-219 ETACS-ECU connector terminal No.20 and fusible link (26).







note Prior to the wiring harness inspection, check joint connectors C-32 <LH drive vehicles>, C-31 <RH drive vehicles>, intermediate connector C-125 and junction block connector C-203, 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 4. Resistance measurement at the C-219 ETACS-ECU connector.


(1)Remove the ETACS-ECU, and measure at the junction block side.

(2)Resistance between C-219 ETACS-ECU connector terminal No.3 and body earth
OK: 2 Ω or less

Q. Is the check result normal?

Go to Step 6.

Go to Step 5.

Step 5. Check the wiring harness between C-219 ETACS-ECU connector terminal No.3 and body earth.




note Prior to the wiring harness inspection, check junction block connector C-205, and repair if necessary.

  • 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 6. Connector check: C-221 ETACS-ECU connector and C-301 column switch connector




Q. Is the check result normal?

Go to Step 7.

Repair the defective connector.

Step 7. 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 8.

Repair the wiring harness.

Step 8. ECU check by using the SWS monitor

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

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.