Inspection Procedure 24: Glow System










OPERATION



  • The glow plug "ON" signal is inputted from the engine-ECU (terminal No. 90) to the glow plug relay (terminal No. 8).
  • The battery voltage is applied to the glow plug relay from battery. When turning on the power transistor in the unit, the glow plug relay applies the battery voltage to the glow plug on each cylinder from the glow plug relay (terminal No. 1, No. 2, No. 6 and No. 7)
  • The glow plug relay (terminal No. 3) outputs a signal, which is input into the engine-ECU (terminal No. 113)

FUNCTION



  • When the ignition switch "ON" signal is input to the engine-ECU, it turns on the glow plug 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 plug relay
  • Failed glow plug
  • Open/short circuit or harness damage in glow plug relay circuit or loose connector contact
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-19 glow plug relay connector

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

STEP 2. Perform voltage measurement at B-19 glow plug relay connector.

  • Disconnect connector, and measure at the harness side.
  • Voltage between power supply and earth.
OK: System voltage

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

    Check intermediate connector A-61, and repair if necessary. If intermediate connector is normal, check harness between the B-19 glow plug relay connector and battery.

    • Check power supply line for open/short circuit.

STEP 3. Perform resistance measurement at B-19 glow plug relay.

  • Disconnect connector, and measure at the harness side.
  • Resistance between earth terminal and earth.
OK: Continuity (2 Ω or less)

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

    Check harness between the B-19 glow plug relay connector and body earth.

    • Check earthing line for open circuit and damage.

STEP 4. Connector check: B-16, B-17 engine-ECU connector

Q. Is the check result normal?
Go to Step 5 .
Repair or replace the connector.

STEP 5. Check harness between B-19 (terminal No. 3) glow plug relay connector and B-16 (terminal No. 113) engine-ECU connector.

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

Q. Is the check result normal?
Go to Step 6 .
Repair the damaged harness wire.

STEP 6. Check harness between B-19 (terminal No. 8) glow plug relay connector and B-17 (terminal No. 90) engine-ECU connector.

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

Q. Is the check result normal?
Go to Step 7 .
Repair the damaged harness wire.

STEP 7. Check harness between B-19 glow plug relay connector and battery.
note Before checking harness, check intermediate connector A-61, and repair if necessary

  • Check power supply line for damage.

Q. Is the check result normal?
Go to Step 8 .

    Repair the damaged harness wire.

STEP 8. Connector check: B-114 block heater connector

Q. Is the check result normal?
Go to Step 9 .
Repair or replace the connector.

STEP 9. Check harness between glow plug relay connector and block heater connector.



  1. Check harness between B-19 (terminal No. 1) glow control relay connector and B-114 block heater connector.
  2. Check harness between B-19 (terminal No. 2) glow control relay connector and B-114 block heater connector.
  3. Check harness between B-19 (terminal No. 6) glow control relay connector and B-114 block heater connector.
  4. Check harness between B-19 (terminal No. 7) glow control relay connector and B-114 block heater connector.

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

Q. Is the check result normal?
Go to Step 10 .
Repair the damaged harness wire.

STEP 10. Replace the block heater.

  • After replacing the block heater, re-check the trouble symptoms.

Q. Does trouble symptom persist?
Go to Step 11 .
The check is end.

STEP 11. Replace the glow plug relay.

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

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