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Inspection Procedure 3: Abnormality in KOS-ECU power supply and ground circuits.
 
 
cautionBefore 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
 
 
DIAGNOSIS
STEP 1. Check KOS-ECU connector C-10 and ETACS-ECU connector C-417 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Is the KOS-ECU connector C-10 and ETACS-ECU connector C-417 in good condition?
Go to Step 2.
Repair the defective connector.
 
STEP 2. Check the wiring harness between the KOS-ECU connector C-10 (terminal No. 7, 8) and the ETACS-ECU connector C-417 (terminal No. 5, 10) and between the KOS-ECU connector C-10 (terminal No. 4) and the body ground.
  • Check the power supply line for open and short circuit, and check the ground line for open circuit.
noteAlso check joint connector (2) C-04, joint connector (4) C-108, grounding connector C-01 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector (2) C-04, joint connector (4) C-108, grounding connector C-01 is damaged, repair or replace the damaged component(s) as described in GROUP 00E, Harness Connector Inspection .
Is the wiring harness between KOS-ECU connector C-10 (terminal No. 7, 8) and the ETACS-ECU connector C-417 (terminal No. 5, 10) and between the KOS-ECU connector C-10 (terminal No. 4) and the body ground in good condition?
Go to Step 3.
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
Does the abnormality in KOS-ECU power supply and ground circuits in good condition?
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 KOS-ECU and register the ID codes. (Refer to .)