Malfunction of ETACS-ECU power supply circuit








COMMENTS ON TROUBLE SYMPTOM


If the ETACS-ECU functions do not work at all, the ETACS-ECU power supply system, earth system, or ETACS-ECU may have a problem.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-315, C-317 ETACS-ECU connector

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

STEP 2. Resistance measurement at the C-315 and C-317 ETACS-ECU connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the resistance between the C-315 ETACS-ECU connector terminal No. 17 and the body earth.
OK: Continuity exists (2 Ω or less)
(3)Measure the resistance between the C-317 ETACS-ECU connector terminal No. 15 and the body earth.
OK: Continuity exists (2 Ω or less)

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

STEP 3. Wiring harness check between the C-315 or C-317 ETACS-ECU connector terminal No. 17 or 15 and the body earth

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. Connector check: C-307 and C-309 ETACS-ECU connector

Q. Is the check result normal?
Go to Step 5.
Repair the defective connector.

STEP 5. Voltage measurement at the C-307 ETACS-ECU connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the voltage between the C-307 ETACS-ECU connector terminal No. 2 and the body earth.
OK: Battery voltage

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

STEP 6. Wiring harness check between the C-307 ETACS-ECU connector terminal No. 2 and the fusible link (34).

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 7. Voltage measurement at the C-309 ETACS-ECU connector.
(1)Disconnect the connector, and measure at the wiring harness side.
(2)Measure the voltage between the C-309 ETACS-ECU connector terminal No. 1 and the body earth.
OK: Battery voltage

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

STEP 8. Wiring harness check between the C-309 ETACS-ECU connector terminal No. 1 and the fusible link (33).

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 9. Retest the system
Check that the ETACS-ECU 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 ETACS-ECU.