Inspection Procedure 25: Glow system










OPERATION



  • The engine-ECU controls the glow plug relay based on the signal of the engine coolant temperature sensor in order to easily start the engine at the cool condition.

PROBABLE CAUSES



  • Failed glow control relay
  • Failed glow plug
  • Damaged harness (Open or short circuit between engine-ECU and glow plug relay, and open or short circuit between glow plug relay and glow plug, Open circuit between engine control relay and glow plug relay, glow plug relay and battery)
  • Damaged connector (Engine-ECU connector, glow plug relay connector)
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector checks: B-34, B-35 and B-36 glow plug relay connectors.

Q. Are the check results normal?
Go to Step 2 .
Repair or replace.

STEP 2. Check the glow plug relay itself.

  • Check the glow plug relay itself (Refer to GROUP 16 - Glow System - On-vehicle Service - Glow Plug Relay Check ).

Q. Is the check result normal?
Go to Step 3 .
Replace the glow plug relay.

STEP 3. Perform voltage measurement at B-35 glow plug relay connector.

  • Disconnect connector, and measurement at harness side.
  • Voltage between terminal No. 1 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 4 .
Check harness between battery and B-35 (terminal No. 1) glow plug relay connector.

STEP 4. Perform voltage measurement at B-34 glow plug relay connector.

  • Disconnect connector, and measurement at harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 1 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 5 .
Check harness between B-34 (terminal No. 1) glow plug relay connector and B-15X (terminal No. 1) engine control relay connector.

STEP 5. Check glow plug itself.

  • Check glow plug itself (Refer to GROUP 16 - Glow System - On-vehicle Service - Glow Plug Check ).

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

STEP 6. Check harness between B-36 (terminal No. 1) glow plug relay connector and B-123 (terminal No. 1) glow plug connector.

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

STEP 7. Connector check: D-213 engine-ECU connector.

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

STEP 8. Check harness between B-34 (terminal No. 2) glow plug relay connector and D-213 (terminal No. 20) engine-ECU connector.

Q. Is the check result normal?
Replace the engine-ECU. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - Precautions Before Service - How to Perform Chassis Number Writing ). After replacing the engine-ECU, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ). After registering the injector identification code, the vehicle equipped with the closed type DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).
Repair the harness wire.