Inspection Procedure 5: Starting Impossible (No Initial Combustion) <Vehicles with AS&G system>

OPERATION

The battery voltage is applied to the engine control relay (terminal No. 1 and terminal No. 3).
The engine-ECU (terminal No. 116) makes the power transistor in the unit be in "ON" position and makes currents go on the starter cut relay coil, and that makes the relay be in "ON" position.
When the starter cut relay is in "ON" position, the battery voltage is supplied to the starter control relay (terminal No. 3) from the starter cut relay (terminal No. 4).
The engine-ECU (terminal No. 125) makes the power transistor in the unit be in "ON" position and makes currents go on the starter control relay coil, and that makes the relay be in "ON" position.
When the starter control relay is in "ON" position, the battery voltage is supplied to the starter (terminal No. 1) from the starter control relay (terminal No. 4).

FUNCTION

When the ignition switch ST signal is input under the condition that the transmission is in the neutral position or the clutch pedal is depressed, the engine-ECU, at the engine start, turns the starter cut relay ON as well as turns the starter control relay ON. Accordingly, the battery voltage is supplied to the starter.
For the engine start from the auto stop status, the engine-ECU turns the starter cut relay ON as well as turns the starter control relay ON when the clutch pedal is depressed while the transmission is placed in the neutral position. Accordingly, the battery voltage is supplied to the starter.

PROBABLE CAUSES

Failed starter cut relay
Failed starter control relay
Open or shorted starter cut relay and starter control relay circuit, harness damage, or connector damage
Failed engine-ECU
Failed battery
Failed starter motor

DIAGNOSIS PROCEDURE

STEP 1. Check battery voltage.

Measure battery voltage during cracking.

OK: 8 V or more

Q. Is the check result normal?

	Go to Step 2 .

	Check battery (Refer to GROUP 54A - Battery - On-vehicle Service - Battery test ).

STEP 2. M.U.T.-III data list

Item No. 27: Cranking signal

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

Q. Is the check result normal?

	Go to Step 9 .

	Go to Step 3 .

STEP 3. Connector check: A-09 engine-ECU connector

Q. Is the check result normal?

Go to Step 4 .

Repair or replace the connector.

STEP 4. Perform voltage measurement at A-09 engine-ECU connector.

Disconnect connector, and measure at the harness side.
Ignition switch: ST
Voltage between terminal No. 80 and earth.

OK: System voltage

Q. Is the check result normal?

Go to Step 7 .

Go to Step 5 .

STEP 5. Connector check: B-240 ignition switch connector

Q. Is the check result normal?

Go to Step 6 .

Repair or replace the connector.

STEP 6. Check ignition switch.

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

Q. Is the check result normal?

Check power supply line for open/short circuit.

Replace ignition switch.

STEP 7. Connector check: B-240 ignition switch connector

Q. Is the check result normal?

Go to Step 8 .

Repair or replace the connector.

STEP 8. Check harness between B-240 (terminal No. 5) ignition switch connector and A-09 (terminal No. 80) engine-ECU connector.

note

Before checking harness, check intermediate connectors B-117 and repair if necessary.

Check output line for damage.

Q. Is the check result normal?

Replace the engine-ECU then perform the variant coding (Refer to GROUP 00 - Precautions Before Service - How to Perform Variant Coding

Repair the damaged harness wire.

STEP 9. Connector check: B-205 starter cut relay connector

Q. Is the check result normal?

Go to Step 10 .

Repair or replace the connector.

STEP 10. Check starter cut relay.

Check starter cut relay (Refer to GROUP 16 - On-vehicle service - Starter Relay Check ).

Q. Is the check result normal?

	Go to Step 11 .

	Replace the starter cut relay.

STEP 11. Perform voltage measurement at B-205 starter cut relay connector.

Remove relay, and measure at J/B side.
Ignition switch: ON
Voltage between terminal No. 1 and earth, also between terminal No. 3 and earth.

OK: System voltage

Q. Is the check result normal?

Go to Step 12 .

Check power supply line for open/short circuit.

STEP 12. Connector check: A-09 engine-ECU connector

Q. Is the check result normal?

Go to Step 13 .

Repair or replace the connector.

STEP 13. Perform voltage measurement at A-09 engine-ECU connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal No. 116 and earth.

OK: System voltage

Q. Is the check result normal?

Go to Step 14 .

Check earthing line for open/short circuit.

STEP 14. Connector check: B-220 starter control relay connector

Q. Is the check result normal?

Go to Step 15 .

Repair or replace the connector.

STEP 15. Check starter control relay.

Check starter control relay (Refer to GROUP 16 - On-vehicle service - Starter Relay Check

Q. Is the check result normal?

	Go to Step 16 .

	Replace the starter control relay.

STEP 16. Perform voltage measurement at B-220 starter control relay connector.

Remove relay, and measure at J/B side.
Using a jumper wire, connect A-09 (terminal No. 116) engine-ECU connector and earth.
Ignition switch: ON
Voltage between terminal No. 3 and earth.

OK: System voltage

Q. Is the check result normal?

Go to Step 21 .

Go to Step 17 .

STEP 17. Check harness between B-220 (terminal No. 3) starter control relay connector and B-205 (terminal No. 4) starter cut relay connector.

note

Before checking harness, check intermediate connectors B-230, B-117 and B-209, and repair if necessary.

Check power supply line for open/short circuit.

Q. Is the check result normal?

Go to Step 18 .

Repair the damaged harness wire.

STEP 18. Check harness between B-205 (terminal No. 4) starter cut relay connector and A-09 (terminal No. 115) engine-ECU connector.

note

Before checking harness, check intermediate connector B-209, and repair if necessary.

Check output line for short circuit.

Q. Is the check result normal?

Go to Step 19 .

Repair the damaged harness wire.

STEP 19. Check harness between B-205 (terminal No. 2) starter cut relay connector and A-09 (terminal No. 116) engine-ECU connector.

note

Before checking harness, check intermediate connector B-209, and repair if necessary.

Check earthing line for damage.

Q. Is the check result normal?

Go to Step 20 .

Repair the damaged harness wire.

STEP 20. Connector check: B-240 ignition switch connector

Q. Is the check result normal?

Go to Step 8 .

Check power supply line for damage.

STEP 21. Perform resistance measurement at B-220 starter control relay connector.

Remove relay, and measure at J/B side.
Resistance between terminal No. 2 and earth.

OK: Continuity (2 Ω or less)

Q. Is the check result normal?

Go to Step 22 .

Check earthing line for open circuit and damage.

STEP 22. Perform voltage measurement at B-220 starter control relay connector.

Remove relay, and measure at J/B side.
Ignition switch: ST
Voltage between terminal No. 1 and earth.

OK: System voltage

Q. Is the check result normal?

Go to Step 24 .

Go to Step 23 .

STEP 23. Check harness between B-220 (terminal No. 1) starter control relay connector and A-09 (terminal No. 125) engine-ECU connector.

note

Before checking harness, check intermediate connectors B-231 and B-117, and repair if necessary.

Check power supply line for open/short circuit.

Q. Is the check result normal?

Replace the engine-ECU then perform the variant coding (Refer to GROUP 00 - Precautions Before Service - How to Perform Variant Coding

Repair the damaged harness wire.

STEP 24. Connector check: A-116 starter connector

Q. Is the check result normal?

Go to Step 25 .

Repair or replace the connector.

STEP 25. Perform voltage measurement at A-116 starter connector.

Disconnect A-09 engine-ECU connector
Disconnect connector, and measure at harness side.
Ignition switch: ON
Using a jumper wire, connect A-09 (terminal No. 125 and terminal No. 116) engine-ECU connector and earth.
Voltage between terminal No. 1 and earth.

OK: System voltage

Q. Is the check result normal?

Go to Step 29 .

Go to Step 26 .

STEP 26. Check harness between B-220 (terminal No. 4) starter control relay connector and A-116 (terminal No. 1) starter connector.

note

Before checking harness, check intermediate connectors A-231, B-117 and A-13, and repair if necessary.

Check power supply line for open/short circuit and damage.

Q. Is the check result normal?

Go to Step 27 .

Repair the damaged harness wire.

STEP 27. Check harness between B-220 (terminal No. 4) starter control relay connector and A-09 (terminal No. 120) engine-ECU connector.

note

Before checking harness, check intermediate connectors A-231, B-117, A-13, and repair if necessary.

Check output line for short circuit.

Q. Is the check result normal?

Go to Step 28 .

Repair the damaged harness wire.

STEP 28. Check harness between B-220 (terminal No. 1) starter control relay connector and A-09 (terminal No. 125) engine-ECU connector.

note

Before checking harness, check intermediate connectors B-231 and B-117, and repair if necessary.

Check power supply line for damage.

Q. Is the check result normal?

Replace the engine-ECU then perform the variant coding (Refer to GROUP 00 - Precautions Before Service - How to Perform Variant Coding

Repair the damaged harness wire.

STEP 29. Check harness between B-220 (terminal No. 4) starter control relay connector and A-116 (terminal No. 1) starter connector.

note

Before checking harness, check intermediate connectors B-231, B-117 and A-13, and repair if necessary.

Check power supply line for damage.

Q. Is the check result normal?

Go to Step 30 .

Repair the damaged harness wire.

STEP 30. Check harness between B-220 (terminal No. 3) starter control relay connector and B-205 (terminal No. 4) starter cut relay connector.

note

Before checking harness, check intermediate connectors B-230, B-117 and B-209, and repair if necessary.

Check power supply line for damage.

Q. Is the check result normal?

Go to Step 31 .

Repair the damaged harness wire.

STEP 31. Connector check: A-117 starter connector

Q. Is the check result normal?

Go to Step 32 .

Repair or replace the connector.

STEP 32. Perform voltage measurement at A-117 starter connector.

Disconnect connector, and measure at the harness side.
Voltage between terminal No. 1 and earth.

OK: System voltage

Q. Is the check result normal?

Go to Step 33 .

Check power supply line for open/short circuit.

STEP 33. Check harness between A-117 (terminal No. 1) starter connector and battery.

Check power supply line for damage.

Q. Is the check result normal?

Replace the starter.

Repair the damaged harness wire.