Inspection Procedure 2: Starting Impossible (starter not operative)


OPERATION



  • The ignition switch-ST signal is inputted into the AS&G-ECU connector terminal ST2 from the ETACS-ECU connector terminal ST2.
  • The battery voltage is supplied to the starter relay connector terminal from the battery.
  • The AS&G-ECU connector terminal STR, STRL turns ON the power transistor in the unit, and then makes the current flow into the starter relay terminal to turn ON the relay.
  • When the starter relay is turned ON, the battery voltage is supplied to the starter connector terminal from the starter relay connector terminal.
  • The starter relay terminal is earthed to the vehicle body.

COMMENTS ON TROUBLE SYMPTOM



  • The failure could possibly be caused by the malfunction of the starter or starter system circuits. If the engine-ECU, KOS-ECU or OSS-ECU stores the diagnosis code, the engine start should be restricted.

PROBABLE CAUSES



  • Failed battery
  • Failed ignition switch
  • Failed starter relay
  • Failed starter motor
  • Open/short circuit or harness damage in ignition switch-ST circuit, or loose connector contact
  • Open/short circuit or harness damage in starter relay circuit, or loose connector contact
  • Failed inhibitor switch
  • Failed ETACS-ECU
  • Failed AS&G-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check battery
Check battery (Refer to GROUP 54A - Battery - On-vehicle Service - Battery Test ).

Q. Is the check result normal?
Go to Step 2.
Replace the battery.

STEP 2. M.U.T.-III diagnosis code
Confirm the diagnosis code is set from the engine-ECU.

Q. Is the diagnosis code set?
Perform the troubleshooting of the engine-ECU (Refer to GROUP 13C - Troubleshooting - Inspection Chart for Diagnosis Code ).
NO (Vehicles without OSS) : Go to Step 4.
NO (Vehicles with OSS) : Go to Step 3.

STEP 3. M.U.T.-III diagnosis code
Confirm the diagnosis code is set from the KOS-ECU.

Q. Is the diagnosis code set?
Perform the troubleshooting of the KOS-ECU (Refer to GROUP 42B - Troubleshooting - Inspection Chart for Diagnosis Code).
Go to Step 4.

STEP 4. M.U.T.-III data list

  • Item 1: Starter switch
OK:
    ON (Ignition switch: ST)
    OFF (Ignition switch: ON)

Q. Is the check result normal?
Go to Step 12.
Go to Step 5.

STEP 5. Perform voltage measurement at ETACS-ECU connector by back probing.

  • Do not disconnect connector.
  • Clutch pedal: Fully depressed
  • Ignition switch: ST
  • Voltage between terminal ST and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 8.
NO <Vehicles without OSS> : Go to Step 6.
NO <Vehicles with OSS> : Go to Step 7.

STEP 6. Check ignition switch itself.
Check ignition switch itself (Refer to GROUP 54A - Ignition Switch - Inspection - Ignition Switch Continuity 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 ST line between ignition switch connector and ETACS-ECU connector.
Replace the ignition switch.

STEP 7. Check of short to power supply, short to earth, open circuit and harness damage in ST 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 8. Continuity check on ETACS-ECU connectors.

  • Disconnect connectors, and check at ETACS-ECU side.
  • Continuity check between terminal ST and ST2.
OK: Continuity

Q. Is the check result normal?
Go to Step 9.
Replace the ETACS-ECU.

STEP 9. Check of short to power supply, short to earth, open circuit and harness damage in ST2 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 short to earth in ST2 line between ETACS-ECU connector and engine-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 ).

STEP 12. Check the starter relay itself.
Check the starter relay itself (Refer to GROUP 16 - Starting System - On-vehicle Service - Starter Relay Continuity Check ).

Q. Is the check result normal?
Go to Step 13.
Replace the starter relay.

STEP 13. Perform resistance measurement at starter relay connector.

  • Remove the relay, and measure at relay box side.
  • Resistance between terminal earth line and body earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?
Go to Step 14.

    Repair the connector(s), or check of open circuit, and harness damage in earthing line between starter relay connector and body earth.

STEP 14. Check of short to power supply, short to earth, open circuit and harness damage in power supply line between battery and starter relay connector.

Q. Is the check result normal?
Go to Step 15.
Repair the connector(s) or wiring harness.

STEP 15. Check the inhibitor switch.
Check the inhibitor switch (Refer to GROUP 23A - On- Vehicle Service - Essential Service - Inhibitor Switch Continuity Check ).

Q. Does the trouble symptom persist?
Go to Step 16.
Replace the inhibitor switch.

STEP 16. Check of short to power supply, short to earth, open circuit and harness damage in output line between inhibitor switch connector and starter relay connector.

Q. Is the check result normal?
Go to Step 17.
Repair the connector(s) or wiring harness.

STEP 17. Check of short to power supply, short to earth, open circuit and harness damage in STRL line between AS&G-ECU connector and inhibitor switch connector.

Q. Is the check result normal?
Go to Step 18.
Repair the connector(s) or wiring harness.

STEP 18. Check of short to power supply, short to earth, open circuit and harness damage in NTSW line between engine-ECU connector and starter relay connector.

Q. Is the check result normal?
Go to Step 19.
Repair the connector(s) or wiring harness.

STEP 19. Check of short to power supply, short to earth, open circuit and harness damage in STR line between AS&G-ECU connector starter relay connector.
Check signal line for open/short circuit and damage.

Q. Is the check result normal?
Go to Step 20.
Repair the connector(s) or wiring harness.

STEP 20. Check of short to earth in output line between starter relay connector and starter connector.

Q. Is the check result normal?
Go to Step 21.
Repair the connector(s) or wiring harness.

STEP 21 Check of short to earth, open circuit and harness damage in power supply line between battery and starter.

Q. Is the check result normal?
Go to Step 22.
Repair the terminal(s) or wiring harness.

STEP 22. Replace the starter assembly.
After replacing the starter assembly, re-check the trouble symptoms.

Q. Is the check result normal?
Replace the AS&G-ECU.
The procedure is complete.