Inspection Procedure
4: Starter Impossible (Starter not Operative)
OPERATION
- The power source is supplied from the battery to the starter connector 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
- The failure could possibly be caused by the malfunction of the starter or
starter system circuits.
PROBABLE CAUSES
- Failed battery
- Failed ignition switch <Vehicles without KOS>
- Failed OSS-ECU <Vehicles with KOS>
- 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 13.
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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 8 <Vehicles without KOS>.
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YES : Go to Step 9 <Vehicles with KOS>.
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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 7.
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NO : Go to Step 5 <Vehicles without KOS>.
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NO : Go to Step 6 <Vehicles with KOS>.
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STEP 5. Check ignition switch itself.
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- Check ignition switch itself (Refer to GROUP 54A - Ignition Switch - Ignition
Switch - Ignition Switch Check).
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Q.
Is the check result normal?
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![](../../../buttons/03btn001.png)
Repair ST line between ignition switch connector
and ETACS-ECU connector.
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Replace the ignition switch.
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STEP 6. Check of open circuit and short to earth in STO 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 <OSS-ECU> - Trouble
Symptom Chart).
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Repair the connector(s) or wiring harness.
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STEP 7. Continuity check on ETACS-ECU connectors
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(1)Disconnect the connector, and measure at ETACS-ECU side.
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(2)Continuity check between terminal ST and ST2 OK: Continuity
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Q.
Is the check result normal?
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![](../../../buttons/03btn001.png)
Repair ST2 line between ETACS-ECU connector
and engine-ECU connector.
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Replace the ETACS-ECU.
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STEP 8. Check of damage in ST line between ignition switch connector
and ETACS-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 9. Check of damage in STO line between OSS-ECU connector and
OSS-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. Continuity check on ETACS-ECU connectors
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(1)Disconnect connectors, and measure at ETACS-ECU side.
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(2)Continuity check between terminal ST and ST2 OK: Continuity
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Q.
Is the check result normal?
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Go to Step 11.
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Replace the ETACS-ECU.
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STEP 11. Check of 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 12.
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Repair the connector(s) or wiring harness.
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STEP 12. 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 13. 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 14.
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Replace the starter relay.
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STEP 14. Resistance measurement at starter relay connector (body earth
line).
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(1)Remove relay, and measure at relay box side.
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(2)Measure 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 15.
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![](../../../buttons/03btn002.png)
Repair body earth line between starter relay connector
and body earth.
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STEP 15. Check of open circuit, short to earth, and damage 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 16.
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Repair the connector(s) or wiring harness.
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STEP 16. Perform voltage measurement at starter relay connector (STRL
line).
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- Remove relay, and measure at relay box side.
- Transmission: P or N range
- Ignition switch: ST
- Voltage between terminal starter relay connector (STRL line) and body earth.
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Q.
Is the check result normal?
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Go to Step 21.
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NO : Go to Step 17.
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STEP 17. Check inhibitor switch
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- Check inhibitor switch (Refer to GROUP 23C - On-vehicle Service - A/T
Control Component Check - Inhibitor Switch Check).
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Q.
Is the check result normal?
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Go to Step 18.
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Replace the inhibitor switch.
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STEP 18. Check of open circuit and short to earth in power supply
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 19.
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Repair the connector(s) or wiring harness.
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STEP 19. Check of open circuit and short to earth 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 20.
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Repair the connector(s) or wiring harness.
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STEP 20. 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 21. Voltage measurement at starter relay connector (power supply
line).
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(1)Remove relay, and measure at 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 22.
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![](../../../buttons/03btn002.png)
Repair output line between battery and engine-ECU connector.
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STEP 22. Voltage measurement at starter connector (output 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 (output line) and body earth. OK: System voltage
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Q.
Is the check result normal?
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Go to Step 26.
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Go to Step 23.
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STEP 23. Check of open circuit and short to earth in output line between
starter relay connector and starter connector.
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Q.
Is the check result normal?
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YES : Go to Step 24.
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Repair the connector(s) or wiring harness.
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STEP 24. Check inhibitor switch
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- Check inhibitor switch (Refer to GROUP 23C - On-vehicle Service - A/T
Control Component Check - Inhibitor Switch Check).
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Q.
Is the check result normal?
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Go to Step 25.
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Replace the inhibitor switch.
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STEP 25. Check of damage in power supply line between inhibitor switch
connector and starter relay connector.
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Q.
Is the check result normal?
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![](../../../buttons/03btn001.png)
Repair 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 26. Check of damage in power supply line between battery and
starter relay valve connector.
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Q.
Is the check result normal?
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Go to Step 27.
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Repair the connector(s) or wiring harness.
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STEP 27. Check of damage in output line between starter relay connector
and starter connector connector.
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Q.
Is the check result normal?
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Go to Step 28.
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Repair the connector(s) or wiring harness.
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STEP 28. 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)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 29.
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![](../../../buttons/03btn002.png)
Repair power supply line between battery connector and
engine-ECU connector.
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STEP 29. Check of 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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