Inspection Procedure 22: Glow System














OPERATION



  • The battery voltage is applied to the glow control relay (terminal No. 5) from the engine control relay (terminal No. 2).
  • The glow plug "ON" signal is inputted from the engine-ECU (terminal No. 112) to the glow control relay (terminal No. 9).
  • The battery voltage is applied to the glow control relay (terminal No. 8) from battery. When turning on the power transistor in the unit, the glow control relay applies the battery voltage to the glow plug (terminal No. 1) on each cylinder from the glow control relay (terminal No. 1, No. 2, No. 3 and No. 4)
  • The glow control relay (terminal No. 7) outputs a signal, which is input into the engine-ECU (terminal No. 101)

FUNCTION



  • When the ignition switch "ON" signal is input to the engine-ECU, it turns on the glow control relay depending on the engine coolant temperature. Then the battery voltage is supplied to the glow plugs to assure the optimum cold starting.

PROBABLE CAUSES



  • Failed glow control relay
  • Failed glow plug
  • Open/short circuit or harness damage in glow control relay circuit or loose connector contact
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: A-30X glow control relay connector

Q. Is the check result normal?
Go to Step 2 .
Repair or replace the connector.

STEP 2. Perform voltage measurement at A-30X glow control relay connector.

  • Disconnect connector, and measure at the harness side.
  • Voltage between terminal No. 8 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 3 .

    Check harness between the A-30X (terminal No. 8) glow control relay connector and battery.

    • Check power supply line for open/short circuit.

STEP 3. Perform voltage measurement at A-30X glow control relay connector.

  • Disconnect connector, and measure at the harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 5 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 5 .
Go to Step 4 .

STEP 4. Connector check: A-33X engine control relay connector.

Q. Is the check result normal?

    Check harness between the A-33X (terminal No. 2) engine control relay connector and A-30X (terminal No. 5) glow control relay connector.

    • Check power supply line for open/short circuit.
Repair or replace the connector.

STEP 5. Perform resistance measurement at A-30X glow control relay.

  • Disconnect connector, and measure at the harness side.
  • Resistance between terminal No. 6 and earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?
Go to Step 6 .

    Check harness between the A-30X (terminal No. 6) glow control relay connector and body earth.

    • Check earthing line for open circuit and damage.

STEP 6. Connector check: B-06 engine-ECU connector

Q. Is the check result normal?
Go to Step 7 .
Repair or replace the connector.

STEP 7. Check harness between A-30X (terminal No. 7) glow control relay connector and B-06 (terminal No. 101) engine-ECU connector.

  • Check output line for open/short circuit and damage.

Q. Is the check result normal?
Go to Step 8 .
Repair the damaged harness wire.

STEP 8. Check harness between A-30X (terminal No. 9) glow control relay connector and B-06 (terminal No. 112) engine-ECU connector.

  • Check output line for open/short circuit and damage.

Q. Is the check result normal?
Go to Step 9 .
Repair the damaged harness wire.

STEP 9. Check harness between B-30X (terminal No. 8) glow control relay connector and battery.

  • Check power supply line for damage.

Q. Is the check result normal?
Go to Step 10 .

    Repair the damaged harness wire.

STEP 10. Connector check: A-33X engine control relay connector.

Q. Is the check result normal?
Go to Step 11 .

    Repair or replace the connector.

STEP 11. Check harness between A-33X (terminal No. 2) engine control relay connector and A-30X (terminal No. 5) glow control relay connector.

  • Check power supply line for damage.

Q. Is the check result normal?
Go to Step 12 .
Repair the damaged harness wire

STEP 12. Connector check: B-03 glow and injector intermediate connector

Q. Is the check result normal?
Go to Step 13 .
Repair or replace the connector.

STEP 13. Check harness between glow control relay connector and glow and injector intermediate connector.



  1. Check harness between A-30X (terminal No. 1) glow control relay connector and B-03 (terminal No. 7) glow and injector intermediate connector.
  2. Check harness between A-30X (terminal No. 2) glow control relay connector and B-03 (terminal No. 3) glow and injector intermediate connector.
  3. Check harness between A-30X (terminal No. 3) glow control relay connector and B-03 (terminal No. 8) glow and injector intermediate connector.
  4. Check harness between A-30X (terminal No. 4) glow control relay connector and B-03 (terminal No. 4) glow and injector intermediate connector.
note Before checking harness, check intermediate connector 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 14 .
Repair the damaged harness wire.

STEP 14. Connector check: B-03-1, B-03-2, B-03-3 and B-03-4 glow plug connector.

Q. Is the check result normal?
Go to Step 15 .
Repair or replace the connector.

STEP 15. Check harness between glow and injector intermediate connector and glow plug connector.



  1. Check harness between B-03 (terminal No. 7) glow and injector intermediate connector and B-03-1 (terminal No. 1) glow plug No. 1 connector.
  2. Check harness between B-03 (terminal No. 3) glow and injector intermediate connector and B-03-2 (terminal No. 1) glow plug No. 2 connector.
  3. Check harness between B-03 (terminal No. 8) glow and injector intermediate connector and B-03-3 (terminal No. 1) glow plug No. 3 connector.
  4. Check harness between B-03 (terminal No. 4) glow and injector intermediate connector and B-03-4 (terminal No. 1) glow plug No. 4 connector.

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

Q. Is the check result normal?
Go to Step 16 .
Repair the damaged harness wire.

STEP 16. Replace the glow plug.

  • After replacing the glow plug, re-check the trouble symptoms.

Q. Does trouble symptom persist?
Go to Step 17 .
The check is end.

STEP 17. Replace the glow control relay.

  • After replacing the glow control relay, re-check the trouble symptoms.

Q. Does trouble symptom persist?
Replace the engine-ECU.
The check is end.