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.
When the ignition switch-ST signal is input to the engine-ECU connector terminal ST, the engine-ECU connector terminal STRL turns ON the power transistor inside the unit, and makes the current flow into the starter relay to turn ON the relay.
When the starter relay is turned ON, the current flows into the starter connector terminal from the starter relay 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
Failed clutch interlock switch
Failed starter relay
Failed starter motor
Open/short circuit or harness damage in starter system circuit or loose connector contact.
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 79: Cranking signal

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

Q. Is the check result normal?

	Go to Step 7.

	Go to Step 3.

STEP 3. Perform voltage measurement at engine-ECU connector.

Disconnect connector, and measure at harness side.
Ignition switch: ST
Voltage between terminal ST and earth.

OK: System voltage

Q. Is the check result normal?

	YES : Go to Step 5.

	Go to Step 4.

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?

	Check and repair connector, or check and repair of short circuit in ST line between ignition switch connector and engine-ECU connector.

	Replace the ignition switch.

STEP 5. Check of damage in ST line between ignition switch connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 6.

	Repair the connector(s) or wiring harness.

STEP 6. M.U.T.-III data list

Item 79: Cranking signal

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 7. 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 8.

	Replace the starter relay.

STEP 8. Perform resistance measurement at starter relay connector.

Remove 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 9.

	Check and repair connector, or check and repair of open circuit, and damage in earthing line between starter relay connector and body earth.

STEP 9. Perform voltage measurement at starter relay connector.

Remove relay, and measure at relay box side.
Clutch pedal: Fully depressed
Ignition switch: ST
Voltage between terminal coil power line and body earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 14.

	NO : Go to Step 10.

STEP 10. Check clutch interlock switch.

Check the clutch interlock switch itself (Refer to GROUP 21A - On-vehicle Service - Clutch Switch Check ).

Q. Is the check result normal?

	Go to Step 11.

	Replace the clutch interlock switch.

STEP 11. Check of open circuit, and short circuit in power supply line between clutch interlock switch connector and starter relay connector.

Q. Is the check result normal?

	Go to Step 12.

	Repair the connector(s) or wiring harness.

STEP 12. Check of open circuit, and short circuit in STRL line between engine-ECU connector and clutch interlock switch connector.

Q. Is the check result normal?

	Go to Step 13.

	Repair the connector(s) or wiring harness.

STEP 13. M.U.T.-III data list

Item 102: 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 14. Perform voltage measurement at starter relay connector.

Remove relay, and measure at relay box side.
Voltage between terminal battery (fusible link) line and earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 15.

	Check and repair connector, or check and repair of open circuit, and short circuit in power supply line between battery and starter relay connector.

STEP 15. Perform voltage measurement at starter connector.

Disconnect connector, and measure at harness side.
Clutch pedal: Fully depressed
Ignition switch: ST
Voltage between terminal starter relay output line and earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 19.

	Go to Step 16.

STEP 16. Check of open circuit, and short circuit in relay output line between starter relay connector and starter connector.

Q. Is the check result normal?

	Go to Step 17.

	Repair the connector(s) or wiring harness.

STEP 17. Check clutch interlock switch.

Check the clutch interlock switch itself (Refer to GROUP 21A - On-vehicle Service - Clutch Switch Check ).

Q. Is the check result normal?

	Go to Step 18.

	Replace the clutch interlock switch.

STEP 18. Check of damage in power supply line between clutch interlock switch connector and starter relay connector.

Q. Is the check result normal?

	Check and repair connector, or check and repair of damage in STRL line between engine-ECU connector and clutch interlock switch connector.

	Repair the connector(s) or wiring harness.

STEP 19. Check of damage in power supply line between battery and starter relay connector.

Q. Is the check result normal?

	Go to Step 20.

	Repair the connector(s) or wiring harness.

STEP 20. Check of damage 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. Perform voltage measurement at starter terminal.

Disconnect terminal, and measure at harness side.
Voltage between terminal battery line and earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 22.

	Check and repair connector, or check and repair of open circuit, and short circuit in power supply line between battery and starter terminal.

STEP 22. Check 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.