Code No. P0203: No. 3 Injector Circuit Malfunction


OPERATION



  • Driving power is supplied from the engine-ECU (terminal No. 49) to the No. 3 injector (terminal No. 2).
  • The engine-ECU (terminal No. 50) turn on the power transistor to flow current to the No. 3 injector (terminal No. 1).

FUNCTION



  • The engine-ECU monitors peak current during injector drive control to detect disconnection in the No. 3 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. 3 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. Connector check: B-105 No. 3 injector connector

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

STEP 2. Check No. 3 injector itself.

  • Check No. 3 injector itself (Refer to ).

Q. Is the check result normal?
Go to Step 3 .
Replace the No. 3 injector.

STEP 3. Check harness between B-105 (terminal No. 1) No. 3 injector connector and B-09 (terminal No. 50) engine-ECU connector.

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

Q. Is the check result normal?
Go to Step 4 .
Repair the damaged harness wire.

STEP 4. Check harness between B-105 (terminal No. 2) No. 3 injector connector and B-09 (terminal No. 49) 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: B-09 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.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).