Inspection Procedure 10: Engine-ECU Power Supply, Engine Control Relay, Ignition Switch-IG1 System




OPERATION




FUNCTION




PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. Check auxiliary battery.



  • Auxiliary battery check (Refer to GROUP 54A <PHEV> - Auxiliary Battery - On-vehicle Service - Auxiliary Battery Test ).

Q. Is the check result normal?

Go to Step 2.
Replace the auxiliary battery.

STEP 2. Check engine control relay itself.



  • Engine control relay connector check.
  • Check engine control relay itself (Refer to ).

Q. Is the check result normal?

Go to Step 3.
Repair or replace the connector, or replace the engine control relay.

STEP 3. Perform voltage measurement at engine control relay connector



  • Remove relay, and measure at relay box side.
  • Voltage between terminal power supply lines and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 4.

    Repair or replace the connector, or check and repair harness between auxiliary battery and engine control relay connector power supply lines.

    • Check power supply line for open/short circuit.

STEP 4. Perform voltage measurement at engine-ECU connector.



  • Disconnect connector, and measure at harness side.
  • Voltage between terminal C/R and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 5.

    Repair or replace the connector, or check and repair harness between engine control relay connector terminal and engine-ECU connector terminal C/R.

    • Check signal line for open/short circuit.

STEP 5. Perform voltage measurement at engine-ECU connector.



  • Disconnect connector, and measure at harness side.
  • Short-circuit engine-ECU connector terminal C/R to the body earth.
  • Voltage between terminal BAT1 and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 8.
Go to Step 6.

STEP 6. Check harness between engine control relay connector terminal and engine-ECU connector terminal BAT1.



  • Check output line for open/short circuit.

Q. Is the check result normal?

Go to Step 7.
Repair or replace the connector, or repair the damaged harness wire.

STEP 7. Check harness between the auxiliary battery and engine control relay connector terminal.



  • Check power supply line for damage.

Q. Is the check result normal?


    Repair or replace the connector, or check and repair harness between engine control relay connector terminal and engine-ECU connector terminal C/R.

    • Check signal line for damage.
Repair or replace the connector, or repair the damaged harness wire.

STEP 8. Check harness between engine-ECU connector terminal BAT1 and engine control relay connector terminal.



  • Check output line for damage.

Q. Is the check result normal?

Go to Step 9.
Repair or replace the connector, or repair the damaged harness wire.

STEP 9. Check harness between auxiliary battery and engine control relay connector terminal.



  • Check power supply line for damage.

Q. Is the check result normal?

Go to Step 10.
Repair or replace the connector, or repair the damaged harness wire.

STEP 10. Perform voltage measurement at engine-ECU connector.



  • Disconnect connector, and measure at harness side.
  • Power supply mode of electric motor switch: ACC
  • Voltage between terminal IGN and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 14.
Go to Step 11.

STEP 11. Perform voltage measurement at ETACS-ECU connector.



  • Disconnect connector, and measure at harness side.
  • Power supply mode of electric motor switch: ACC
  • Voltage between terminal IG1 and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 13.
Go to Step 12.

STEP 12. Check harness between OSS-ECU connector terminal IG1 and ETACS-ECU connector terminal IG1.



  • Check power supply line for open/short circuit.

Q. Is the check result normal?

Perform troubleshooting of OSS System (Refer to GROUP 42B <PHEV> - Troubleshooting <OSS-ECU> - Trouble Symptom Chart ).
Repair or replace the connector, or repair the damaged harness wire.

STEP 13. Continuity check on ETACS-ECU connectors



  • Disconnect connectors, and measure at the ETACS-ECU side.
  • Continuity test between terminal IG1 and IGN.
note Connect the (+) side of circuit tester to terminal IGN.
OK: Continuity

Q. Is the check result normal?


    Repair or replace the connector, or check and repair harness between ETACS-ECU connector terminal IGN and engine-ECU connector terminal IGN.

    • Check signal line for open/short circuit.
Replace the ETACS-ECU.

STEP 14. Check harness between ETACS-ECU connector terminal IGN and engine-ECU connector terminal IGN.



  • Check signal line for damage.

Q. Is the check result normal?

Go to Step 15.
Repair or replace the connector, or repair the damaged harness wire.

STEP 15. Continuity check on ETACS-ECU connectors



  • Disconnect connectors, and measure at the ETACS-ECU side.
  • Continuity test between terminal IG1 and IGN.
note Connect the (+) side of circuit tester to terminal IGN.
OK: Continuity

Q. Is the check result normal?

Go to Step 16.
Replace the ETACS-ECU.

STEP 16. Check harness between OSS-ECU connector terminal IG1 and ETACS-ECU connector terminal IG1.



  • Check power supply line for damage.

Q. Is the check result normal?

Go to Step 17.
Repair or replace the connector, or repair the damaged harness wire.

STEP 17. Check harness between engine-ECU connector terminals GNDB, GNDE and body earth.



  • Check earthing line for open circuit and damage.

Q. Is the check result normal?

Replace the engine-ECU.
Repair or replace the connector, or repair the damaged harness wire.