Code No. P0204: No. 4 Injector Circuit Malfunction


OPERATION



  • Driving power is supplied from the engine-ECU connector terminal I/B4 to the No. 4 injector connector terminal.
  • The engine-ECU connector terminal INJ4 turn on the power transistor to flow current to the No. 4 injector connector terminal.

FUNCTION



  • The engine-ECU monitors peak current during injector drive control to detect disconnection in the No. 4 injector 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 injector circuit is not detected, the circuit is judged to be open.

FAIL-SAFE AND BACKUP FUNCTION



  • The throttle valve is opened (Electrical discontinuity).
  • The EGR control is stopped (fully closed).
  • The DPF regeneration is prohibited.
  • The AS&G control is prohibited.

PROBABLE CAUSES



  • Failed No. 4 injector
  • Open/short circuit or harness damage in 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. Check No. 4 injector itself.

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

Q. Is the check result normal?
Go to Step 2.
Repair or replace the connector, or replace the No. 4 injector.

STEP 2. Check harness between No. 4 injector connector terminal and engine-ECU connector terminal INJ4.

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

Q. Is the check result normal?
Go to Step 3.
Repair or replace the connector, or repair the damaged harness wire.

STEP 3. Check harness between No. 4 injector connector terminal and engine-ECU connector terminal I/B4.

  • Check power supply 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. M.U.T.-III diagnosis code

  • Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?
Replace the engine-ECU.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).