Inspection Procedure 4: Starting Impossible (No Initial Combustion) <Vehicles without 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. 125) makes the power transistor in the unit be in "ON" position and makes currents go on the starter relay coil, and that makes the relay be in "ON" position.
When the starter relay is in "ON" position, the battery voltage is supplied to the starter (terminal No. 1) from the starter relay (terminal No. 4).

FUNCTION

When the ignition switch ST signal is input to the engine-ECU, the engine-ECU places the starter relay in the ON position. Accordingly, the battery voltage is supplied to the starter.

PROBABLE CAUSES

Failed starter relay
Open or shorted starter 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.

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

Q. Is the check result normal?

Go to Step 10 .

Repair or replace the connector.

STEP 10. Check starter relay.

Check starter relay (Refer to GROUP 16 - Starting System-Starter Relay Check ).

Q. Is the check result normal?

	Go to Step 11 .

	Replace the starter relay.

STEP 11. Perform voltage measurement at B-205 starter 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.

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. 125 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: A-116 starter connector.

Q. Is the check result normal?

Go to Step 15 .

Repair or replace the connector.

STEP 15. Perform voltage measurement at A-116 starter connector.

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

OK: System voltage

Q. Is the check result normal?

Go to Step 17 .

Go to Step 16 .

STEP 16. Check harness between B-205 (terminal No. 4) starter relay connector and A-116 (terminal No. 1) starter connector.

note

Before checking harness, check intermediate connectors A-13 and B-212, and repair if necessary.

Check power supply line for open/short circuit and 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 17. Connector check: A-117 starter connector

Q. Is the check result normal?

Go to Step 18 .

Repair or replace the connector.

STEP 18. 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 19 .

Check power supply line for open/short circuit.

STEP 19. 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.