Inspection Procedure 3

Inspection Procedure 3: Abnormality in KOS-ECU power supply and ground circuits.

CAUTION:
Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.

















TECHNICAL DESCRIPTION (COMMENT)

If the KOS-ECU does not work at all or if the KOS-ECU cannot communicate with the scan tool, the KOS-ECU power supply or the ground circuit may be defective.

TROUBLESHOOTING HINTS

- Damaged wiring harness and connectors

- Malfunction of KOS-ECU

STEP 1. Check KOS-ECU connector C-31 and ETACS-ECU connector C-317 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is the KOS-ECU connector C-31 and ETACS-ECU connector C-317 in good condition?

YES Go to Step 2.
NO Repair the defective connector.
STEP 2. Check the wiring harness between the KOS-ECU connector C-31
(terminal No. 38, 39) and the ETACS-ECU connector C-317 (terminal No. 10, 5) and between the KOS-ECU connector C-31 (terminal No. 14) and the body ground.

- Check the power supply line for open and short circuit, and check the ground line for open circuit.

NOTE:
Also check joint connector (1) C-03 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector (1) C-03 is damaged, repair or replace the damaged component(s) as described in Harness Connector Inspection Harness Connector Inspection.

Q. Is the wiring harness between KOS-ECU connector C-31 (terminal No. 38, 39) and the ETACS-ECU connector C-317 (terminal No. 10, 5) and between the KOS-ECU connector C-31 (terminal No. 14) and the body ground in good condition?

YES Go to Step 3.
NO The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
STEP 3. Retest the system

Q. Does the abnormality in KOS-ECU power supply and ground circuits in good condition?

YES The trouble can be an intermittent malfunction How to Cope With Intermittent Malfunctions).
NO Replace KOS-ECU and register the ID codes (Refer to ID registration procedure manual - ID codes registration judgement table).