Inspection Procedure 9: AS&G-ECU Power Supply, Ignition Switch-IG1 System




OPERATION



  • The power voltage is supplied to the AS&G-ECU connector terminal BAT1 from the engine control relay connector terminal.
  • The ignition switch-IG1 signal is inputted into the AS&G-ECU connector terminal IGN from the ETACS-ECU connector terminal IGN.
  • The AS&G-ECU connector terminal GND is earthed to the vehicle body.

PROBABLE CAUSES



  • Open/short circuit or harness damage in engine control relay circuit, or loose connector contact
  • Open/short circuit or harness damage in ignition switch-IG1 circuit, or loose connector contact
  • Open circuit or harness damage in AS&G-ECU earth circuit, or loose connector contact
  • Failed AS&G-ECU

DIAGNOSIS PROCEDURE


STEP 1. Perform voltage measurement at AS&G-ECU connector.



  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal BAT1 and earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 2.

    Repair the connector(s), or check and repair of short to earth and open circuit in BAT1 line between engine control relay connector and AS&G-ECU connector.

STEP 2. Perform voltage measurement at AS&G-ECU connector.



  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal IGN and earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 7.
Go to Step 3.

STEP 3. Perform voltage measurement at ETACS-ECU connector by back probing.



  • Do not disconnect connector.
  • Ignition switch: ON
  • Voltage between terminal IG1 and earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 6.
NO <Vehicles without OSS> : Go to Step 4.
NO <Vehicles with OSS> : Go to Step 5.

STEP 4. Check ignition switch itself.



  • Check ignition switch itself (Refer to GROUP 54A - Ignition Switch - Inspection - Ignition Switch Check ).

Q. Is the check result normal?


    Repair the connector(s), or check and repair of short to power supply, short to earth, open circuit and harness damage in IG1 line between ignition switch connector and ETACS-ECU connector.
Replace the ignition switch.

STEP 5. Check of short to earth and open circuit in IG1 line between OSS-ECU connector and ETACS-ECU connector.


Q. Is the check result normal?

Perform the troubleshooting of the OSS-ECU (Refer to GROUP 42B - Troubleshooting <OSS-ECU> - Symptom Chart ).
Repair the connector(s) or wiring harness.

STEP 6. Continuity check on ETACS-ECU connectors.



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

Q. Is the check result normal?


    Repair the connector(s), or check and repair of short to earth and open circuit in IG1 line between ETACS-ECU connector and AS&G-ECU connector.
Replace the ETACS-ECU.

STEP 7. Perform resistance measurement at AS&G-ECU connector.



  • Disconnect connector, and measure at harness side.
  • Resistance between terminal GND and body earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?

Go to Step 8.

    Repair the connector(s), or check and repair of open circuit and harness damage in GND line between AS&G-ECU connector and body earth.

STEP 8. Continuity check on C-403 and C-417 ETACS-ECU connectors



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

Q. Is the check result normal?

Go to Step 9.
Replace the ETACS-ECU.

STEP 9. Check of harness damage in IGN line between ETACS-ECU connector and AS&G-ECU connector.


Q. Is the check result normal?

Go to Step 10.
Repair the connector(s) or wiring harness.

STEP 10. Check of harness damage in BAT1 line between engine control relay connector and AS&G-ECU connector.


Q. Is the check result normal?

Go to Step 11.
Repair the connector(s) or wiring harness.

STEP 11. Check the trouble symptom.


Q. Does the trouble symptom persist?

Replace the AS&G-ECU.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).