Inspection Procedure
4: Starting Impossible (starter not operative)
OPERATION
- The power source is supplied from the battery to the starter terminal.
- The battery voltage is applied to the starter relay connector terminal.
- When the ignition switch-ST signal is input to the engine-ECU connector terminal
ST2, the engine-ECU connector terminal STRL turns ON the power transistor inside the unit, and
makes the current flow into the starter relay connector terminal to turn ON the relay.
- When the starter relay is turned ON, the current flows into the starter connector
terminal from the starter relay connector terminal to drive the starter motor.
COMMENTS ON TROUBLE SYMPTOM
- Failure is possibly caused by malfunction of starter or starter system circuits.
PROBABLE CAUSES
- Failed battery
- Failed OSS-ECU
- Failed starter relay
- Failed starter motor
- Open/short circuit or harness damage in starter system circuit or loose
connector contact.
- Failed inhibitor switch
- Failed ETACS-ECU
- Failed engine-ECU
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- Check battery (Refer to GROUP 54A - Battery - On-vehicle Service - Battery
Test
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Q.
Is the check result normal?
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 Go to Step 2.
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 Replace the battery.
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STEP 2. M.U.T.-III data list
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OK:
ON (ignition switch: ST)
OFF (ignition switch: ON)
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Q.
Is the check result normal?
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Go to Step 11.
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Go to Step 3.
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STEP 3. Voltage measurement at engine-ECU connector (ST2 terminal).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(3)Check the voltage between the engine-ECU connector (ST2 terminal) and body earth.
OK: System voltage
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Q.
Is the check result normal?
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YES  : Go to Step 7.
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Go to Step 4.
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STEP 4. Voltage measurement at ETACS-ECU connector (ST terminal).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(3)Check the voltage between the ETACS-ECU connector (ST terminal) and body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 6.
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NO : Go to Step 5.
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STEP 5. Check of short to earth, and open circuit in ST line between
OSS-ECU connector and ETACS-ECU connector.
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Q.
Is the check result normal?
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Perform troubleshooting of OSS System (Refer to GROUP 42B - Troubleshooting - Trouble
Symptom Chart ).
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Repair the connector(s) or wiring harness.
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STEP 6. Continuity check on ETACS-ECU connectors.
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(1)Disconnect the connector, and measure at the ETACS-ECU side.
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(2)Continuity check between the ETACS-ECU connector (ST terminal) and the ETACS-ECU
connector (ST2 terminal).
OK: Continuity
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Q.
Is the check result normal?
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Repair or replace the connector(s), or check
and repair the harness of short to earth, and open circuit in ST2 line between ETACS-ECU connector and
engine-ECU connector.
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Replace the ETACS-ECU.
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STEP 7. Check of harness damage in ST line between OSS-ECU connector
and ETACS-ECU connector.
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Q.
Is the check result normal?
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Go to Step 8.
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Repair the connector(s) or wiring harness.
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STEP 8. Continuity check on ETACS-ECU connectors.
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(1)Disconnect the connector, and measure at the ETACS-ECU side.
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(2)Continuity check between the ETACS-ECU connector (ST terminal) and the ETACS-ECU
connector (ST2 terminal).
OK: Continuity
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Q.
Is the check result normal?
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Go to Step 9.
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Replace the ETACS-ECU.
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STEP 9. Check of harness damage in ST2 line between ETACS-ECU connector
and engine-ECU connector.
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Q.
Is the check result normal?
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Go to Step 10.
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Repair the connector(s) or wiring harness.
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STEP 10. M.U.T.-III data list
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OK:
ON (ignition switch: ST)
OFF (ignition switch: ON)
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunctions ).
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Replace the engine-ECU.
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STEP 11. Check starter relay itself.
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- Check starter relay itself (Refer to GROUP 16 - Starting System - On-vehicle
Service - Starter Relay Continuity Check ).
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Q.
Is the check result normal?
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Go to Step 12.
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Replace the starter relay.
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STEP 12. Resistance measurement at starter relay connector (body earth
line).
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(1)Remove relay, and measure at the relay box side.
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(2)Check the resistance between the starter relay connector (body earth line) and
body earth.
OK: Continuity (2 Ω or less)
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Q.
Is the check result normal?
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Go to Step 13.
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Repair or replace the connector(s), or check
and repair the harness of open circuit and damage in body earth line between starter relay connector and
body earth.
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STEP 13. Voltage measurement at starter relay connector (STRL line).
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(1)Remove relay, and measure at the relay box side.
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(2)Transmission: P or N range
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(4)Check the voltage between the starter relay connector (STRL line) and body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 19.
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Go to Step 14.
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STEP 14. Check inhibitor switch
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- Check inhibitor switch (Refer to GROUP 23A - On-vehicle Service - Essential
Service - Inhibitor Switch Continuity Check ).
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Q.
Is the check result normal?
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Go to Step 15.
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Replace the inhibitor switch.
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STEP 15. Check of short to earth, and open circuit in STRL line between
inhibitor switch connector and starter relay connector.
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Q.
Is the check result normal?
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Go to Step 16.
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Repair the connector(s) or wiring harness.
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STEP 16. Check of short to earth, and open circuit in STRL line between
engine-ECU connector and inhibitor switch connector.
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Q.
Is the check result normal?
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Go to Step 17.
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Repair the connector(s) or wiring harness.
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STEP 17. Check of short circuit to earth in NTSW line between engine-ECU
connector and starter relay connector.
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Q.
Is the check result normal?
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Go to Step 18.
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Repair the connector(s) or wiring harness.
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STEP 18. M.U.T.-III data list
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OK:
ON (ignition switch: ST)
OFF (ignition switch: ON)
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunctions ).
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Replace the engine-ECU.
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STEP 19. Voltage measurement at starter relay connector (power supply
line).
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(1)Remove relay, and measure at the relay box side.
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(2)Check the voltage between the starter relay connector (power supply line) and body
earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 20.
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Repair or replace the connector(s), or check
and repair the harness of short to earth, and open circuit in body earth line between battery
and starter relay connector
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STEP 20. Voltage measurement at starter connector (power supply line).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Transmission: P or N range
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(4)Check the voltage between the starter connector (power supply line) and body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 24.
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Go to Step 21.
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STEP 21. Check of short to earth, and open circuit in power supply
line between starter relay connector and starter connector.
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Q.
Is the check result normal?
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Go to Step 22.
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Repair the connector(s) or wiring harness.
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STEP 22. Check inhibitor switch
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- Check inhibitor switch (Refer to GROUP 23C - On-vehicle Service - Essential
Service - Inhibitor Switch Check ).
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Q.
Is the check result normal?
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Go to Step 23.
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Replace the inhibitor switch.
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STEP 23. Check of harness damage in STRL line between inhibitor switch
connector and starter relay connector.
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Q.
Is the check result normal?
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Repair or replace the connector(s), or check
and repair the harness of damage in STRL line between engine-ECU connector and inhibitor switch
connector.
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Repair the connector(s) or wiring harness.
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STEP 24. Check of harness damage in power supply line between battery
and starter relay connector.
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Q.
Is the check result normal?
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Go to Step 25.
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Repair the damaged harness wire.
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STEP 25. Check of harness damage in power supply line between starter
relay connector and starter connector.
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Q.
Is the check result normal?
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Go to Step 26.
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Repair the connector(s) or wiring harness.
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STEP 26. Voltage measurement at starter terminal (power supply line).
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(1)Disconnect the terminal, and measure at the wiring harness side.
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(2)Check the voltage between the starter terminal (power supply line) and body earth.
OK: System voltage
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Q.
Is the check result normal?
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Go to Step 27.
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Repair or replace the connector(s), or check
and repair the harness of short to earth, and open circuit in power supply line between battery
and starter terminal
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STEP 27. Check of harness damage in power supply line between battery
and starter terminal.
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Q.
Is the check result normal?
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Replace the starter.
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Repair the connector(s) or wiring harness.
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