Code No. P0683: Glow Control Unit Communication Abnormality




OPERATION




FUNCTION




TROUBLE JUDGMENT


Check Conditions
Judgment Criterion

FAIL-SAFE AND BACKUP FUNCTION




PROBABLE CAUSES




DIAGNOSTIC PROCEDURE


STEP 1. Perform voltage measurement at glow control unit connector.



  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal engine control relay side power supply line and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 2.

    Repair or replace the connector, or check and repair harness between glow control unit connector terminal and engine control relay connector terminal.

    • Check power supply line for open/short circuit.

STEP 2. Perform resistance measurement at glow control unit connector.



  • Remove the glow control unit, and measure the relay box side.
  • Resistance between terminal earthing line and body earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?

Go to Step 3.

    Check and repair harness between glow control unit connector and body earth.

    • Check earthing line for open circuit and damage.

STEP 3. Check harness between glow control unit connector terminal and engine-ECU connector terminal G/CT.



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

Q. Is the check result normal?

Go to Step 4.
Repair or replace the connector, or repair the damaged harness wire.

STEP 4. Check harness between glow control unit connector terminal and engine-ECU connector terminal G/DA.



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

Q. Is the check result normal?

Go to Step 5.
Repair or replace the connector, or repair the damaged harness wire.

STEP 5. Check harness between glow control unit connector terminal and engine control relay connector terminal.



  • Check power supply line for damage.

Q. Is the check result normal?

Go to Step 6.
Repair or replace the connector, or repair the damaged harness wire.

STEP 6. M.U.T.-III diagnosis code.



  • Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?

Go to Step 7.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 7. Replace the glow control unit.



  • After replacing the glow control unit, reconfirm whether the diagnosis code is set.

Q. Is the diagnosis code set?

Replace the engine-ECU.
Check is end.