Code No. P0204: No. 4 Injector Circuit Malfunction <Euro5b>






OPERATION



  • Driving power is supplied from the engine-ECU (terminal No. 25) to the No. 4 injector (terminal No. 2).
  • The engine-ECU (terminal No. 27) turn on the power transistor to flow current to the No. 4 injector (terminal No. 1).

FUNCTION



  • The engine-ECU monitors peak current during injector drive control to detect disconnection in the injector No. 4 circuit.

TROUBLE JUDGMENT


Check Conditions
  • Ignition switch is in ON position
  • Battery positive voltage is 8 V or more.
  • Except during the engine cranking period
  • When an engine-ECU internal capacitor is allowed to be charged
Judgment Criterion
  • When the peak current of the No. 4 injector circuit is not detected, the circuit is judged to be open.

PROBABLE CAUSES



  • Failed No. 4 injector
  • Open/short circuit or harness damage in No. 4 injector circuit or loose connector contact
  • Failed engine-ECU

DIAGNOSIS PROCEDURE


caution A high-tension voltage is flowing between the engine-ECU and the injectors while the engine is running. Handle them carefully to avoid receiving electric shocks from the voltage.

STEP 1. Connector check: A-129 No. 4 injector connector



Q. Is the check result normal?

Go to Step 2.

Repair or replace the connector.

STEP 2. Check No. 4 injector itself.



  • Check No. 4 injector itself (Refer to ).

Q. Is the check result normal?

Go to Step 3.
Replace the No. 4 injector. After replacing the Injector, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).

STEP 3. Check harness between No. 4 injector connector and engine-ECU connector.




Check harness between A-129 (terminal No. 1) No. 4 injector connector and C-105 (terminal No. 27) engine-ECU connector.

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

Q. Are the check results normal?

Go to Step 4.

Repair the damaged harness wire.

STEP 4. Check harness between A-129 (terminal No. 2) No. 4 injector connector and C-105 (terminal No. 25) engine-ECU connector.





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

Q. Is the check result normal?

Go to Step 5.

Repair or replace the connector.

STEP 5. Connector check: C-105 engine-ECU connector



Q. Is the check result normal?

Go to Step 6.

Repair or replace the connector.

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



  • Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?

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, carry out the forcible DPF regeneration. (Refer to GROUP 17 - Emission Control - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).