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

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 data list

Item 40: Starter switch

OK:
ON (ignition switch: ST)
OFF (ignition switch: ON)

Q. Is the check result normal?

	Go to Step 13.

	Go to Step 3.

STEP 3. Voltage measurement at engine-ECU connector (ST2 terminal).

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Ignition switch: ST

(3)Check the voltage between the engine-ECU connector (ST2 terminal) and body earth.
OK: System voltage

Q. Is the check result normal?

	YES : Go to Step 8 <Vehicles without KOS>.

	YES : Go to Step 9 <Vehicles with KOS>.

	Go to Step 4.

STEP 4. Voltage measurement at ETACS-ECU connector (ST terminal).

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Ignition switch: ST

(3)Check the voltage between the ETACS-ECU connector (ST terminal) and body earth.
OK: System voltage

Q. Is the check result normal?

	Go to Step 7.

	NO : Go to Step 5 <Vehicles without KOS>.

	NO : Go to Step 6 <Vehicles with KOS>.

STEP 5. Check ignition switch itself.

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

Q. Is the check result normal?

	Repair ST line between ignition switch connector and ETACS-ECU connector.

	Replace the ignition switch.

STEP 6. Check of open circuit and short to earth in STO line between OSS-ECU connector and ETACS-ECU connector.

Q. Is the check result normal?

	Perform troubleshooting of OSS System (Refer to GROUP 42B - Troubleshooting <OSS-ECU> - Trouble Symptom Chart).

	Repair the connector(s) or wiring harness.

STEP 7. Continuity check on ETACS-ECU connectors

(1)Disconnect the connector, and measure at ETACS-ECU side.

(2)Continuity check between terminal ST and ST2
OK: Continuity

Q. Is the check result normal?

	Repair ST2 line between ETACS-ECU connector and engine-ECU connector.

	Replace the ETACS-ECU.

STEP 8. Check of damage in ST line between ignition switch connector and ETACS-ECU connector.

Q. Is the check result normal?

	Go to Step 10.

	Repair the connector(s) or wiring harness.

STEP 9. Check of damage in STO line between OSS-ECU connector and OSS-ECU connector.

Q. Is the check result normal?

	Go to Step 10.

	Repair the connector(s) or wiring harness.

STEP 10. Continuity check on ETACS-ECU connectors

(1)Disconnect connectors, and measure at ETACS-ECU side.

(2)Continuity check between terminal ST and ST2
OK: Continuity

Q. Is the check result normal?

	Go to Step 11.

	Replace the ETACS-ECU.

STEP 11. Check of damage in ST2 line between ETACS-ECU connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 12.

	Repair the connector(s) or wiring harness.

STEP 12. M.U.T.-III data list

Item 40: Starter switch

OK:
ON (ignition switch: ST)
OFF (ignition switch: ON)

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).

	Replace the engine-ECU.

STEP 13. Check starter relay itself.

Check 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 14.

	Replace the starter relay.

STEP 14. Resistance measurement at starter relay connector (body earth line).

(1)Remove relay, and measure at relay box side.

(2)Measure the resistance between the starter relay connector (body earth line) and body earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?

	Go to Step 15.

	Repair body earth line between starter relay connector and body earth.

STEP 15. Check of open circuit, short to earth, and damage in NTSW line between engine-ECU connector and starter relay connector.

Q. Is the check result normal?

	Go to Step 16.

	Repair the connector(s) or wiring harness.

STEP 16. Perform voltage measurement at starter relay connector (STRL line).

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.

OK: System voltage

Q. Is the check result normal?

	Go to Step 21.

	NO : Go to Step 17.

STEP 17. Check inhibitor switch

Check inhibitor switch (Refer to GROUP 23C - On-vehicle Service - A/T Control Component Check - Inhibitor Switch Check).

Q. Is the check result normal?

	Go to Step 18.

	Replace the inhibitor switch.

STEP 18. Check of open circuit and short to earth in power supply line between engine-ECU connector and inhibitor switch connector.

Q. Is the check result normal?

	Go to Step 19.

	Repair the connector(s) or wiring harness.

STEP 19. Check of open circuit and short to earth in STRL line between engine-ECU connector and inhibitor switch connector.

Q. Is the check result normal?

	Go to Step 20.

	Repair the connector(s) or wiring harness.

STEP 20. M.U.T.-III data list

Item 413: Starter relay

OK:
ON (ignition switch: ST)
OFF (ignition switch: ON)

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).

	Replace the engine-ECU.

STEP 21. Voltage measurement at starter relay connector (power supply line).

(1)Remove relay, and measure at relay box side.

(2)Check the voltage between the starter relay connector (power supply line) and body earth.
OK: System voltage

Q. Is the check result normal?

	Go to Step 22.

	Repair output line between battery and engine-ECU connector.

STEP 22. Voltage measurement at starter connector (output line).

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Transmission: P or N range

(3)Ignition switch: ST

(4)Check the voltage between the starter connector (output line) and body earth.
OK: System voltage

Q. Is the check result normal?

	Go to Step 26.

	Go to Step 23.

STEP 23. Check of open circuit and short to earth in output line between starter relay connector and starter connector.

Q. Is the check result normal?

	YES : Go to Step 24.

	Repair the connector(s) or wiring harness.

STEP 24. Check inhibitor switch

Check inhibitor switch (Refer to GROUP 23C - On-vehicle Service - A/T Control Component Check - Inhibitor Switch Check).

Q. Is the check result normal?

	Go to Step 25.

	Replace the inhibitor switch.

STEP 25. Check of damage in power supply line between inhibitor switch connector and starter relay connector.

Q. Is the check result normal?

	Repair STRL line between engine-ECU connector and inhibitor switch connector.

	Repair the connector(s) or wiring harness.

STEP 26. Check of damage in power supply line between battery and starter relay valve connector.

Q. Is the check result normal?

	Go to Step 27.

	Repair the connector(s) or wiring harness.

STEP 27. Check of damage in output line between starter relay connector and starter connector connector.

Q. Is the check result normal?

	Go to Step 28.

	Repair the connector(s) or wiring harness.

STEP 28. Voltage measurement at starter connector (power supply line).

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Check the voltage between the starter connector (power supply line) and body earth.
OK: System voltage

Q. Is the check result normal?

	Go to Step 29.

	Repair power supply line between battery connector and engine-ECU connector.

STEP 29. Check of damage in power supply line between battery and starter terminal.

Q. Is the check result normal?

	Replace the starter.

	Repair the connector(s) or wiring harness.