Code No. P0203: No. 3 Injector System
















OPERATION



  • Power is supplied to the injector (terminal No. 1) from the injector relay (terminal No. 3).
  • The engine-ECU (terminal No. 18) makes the power transistor in the unit be in ON position, and that makes currents go on the injector (terminal No. 2).

FUNCTION



  • The engine-ECU controls the power supply interval of the injector.
  • The fuel injection amount of the injector depends on the power supply interval.

TROUBLE JUDGMENT


Check Condition
  • Engine is running.
Judgement Criterion
  • The supply voltage is 3 V or less without the injector driving.
Check Condition
  • Engine is running.
Judgement Criterion
  • The coil current is 4.5 A or more with the injector driving.

PROBABLE CAUSES



  • Failed No. 3 injector
  • Open/short circuit or harness damage in No. 3 injector circuit or loose connector contact
  • Failed engine-ECU

DIAGNOSIS PROCEDURE


STEP 1. M.U.T.-III actuator test



  • Item 3: No. 3 injector
OK: Idling state varies.

Q. Is the check result normal?

Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
Go to Step 2 .

STEP 2. Connector check: B-105 No. 3 injector connector


Q. Is the check result normal?

Go to Step 3 .
Repair or replace the connector.

STEP 3. Check No. 3 injector itself.



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

Q. Is the check result normal?

Go to Step 4 .
Replace the No. 3 injector.

STEP 4. Perform voltage measurement at B-105 No. 3 injector connector.



  • Disconnect connector and measure 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 14 .
Go to Step 5 .

STEP 5. Connector check: A-24X injector relay connector


Q. Is the check result normal?

Go to Step 6 .
Repair or replace the connector.

STEP 6. Check injector relay itself.



  • Check injector relay itself (Refer to Injector Relay Continuity Check ).

Q. Is the check result normal?

Go to Step 7 .
Replace the injector relay.

STEP 7. Perform resistance measurement at A-24X injector relay connector.



  • Remove relay and measure at connector side.
  • Voltage between terminal No. 2 and earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?

Go to Step 8 .

    Check and repair harness between A-24X (terminal No. 2) injector relay connector and body earth.

    • Check earthing line for open circuit and damage.

STEP 8. Perform voltage measurement at A-24X injector relay connector.



  • Remove relay and measure at connector side.
  • Ignition switch: ON
  • Voltage between terminal No. 1 and earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 10 .
Go to Step 9 .

STEP 9. Connector check: C-304 ETACS-ECU connector


Q. Is the check result normal?


    Check and repair harness between C-304 (terminal No. 10) ETACS-ECU connector and A-24X (terminal No. 1) injection relay connector.

    • Check power supply line for open/short circuit.
Repair or replace the connector.

STEP 10. Perform voltage measurement at A-24X injector relay connector.



  • Remove relay and measure at connector side.
  • Ignition switch: ON
  • Voltage between terminal No. 4 and earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 12 .
Go to Step 11 .

STEP 11. Connector check: A-33X engine control relay connector


Q. Is the check result normal?


    Check and repair harness between A-33X (terminal No. 2) engine control relay connector and A-24X (terminal No. 4) injection relay connector.

    • Check power supply line for open/short circuit.
Repair or replace the connector.

STEP 12. Check harness between A-24X (terminal No. 3) injector relay connector and B-105 (terminal No. 1) No. 3 injector connector.


note Before checking harness, check intermediate connector A-13, and repair if necessary.

  • Check power supply line for open/short circuit.

Q. Is the check result normal?

Go to Step 13 .
Repair the damaged harness wire.

STEP 13. Connector check: C-304 ETACS-ECU connector


Q. Is the check result normal?


    Check and repair harness between C-304 (terminal No. 10) ETACS-ECU connector and A-24X (terminal No. 1) injection relay connector.

    • Check power supply line for damage.
Repair or replace the connector.

STEP 14. Connector check: A-33X engine control relay connector


Q. Is the check result normal?

Go to Step 15 .
Repair or replace the connector.

STEP 15. Check harness between A-33X (terminal No. 2) engine control relay connector and A-24X (terminal No. 4) injection relay connector.



  • Check power supply line for damage.

Q. Is the check result normal?

Go to Step 16 .
Repair the damaged harness wire.

STEP 16. Check harness between A-24X (terminal No. 3) injector relay connector and B-105 (terminal No. 1) No. 3 injector connector.


note Before checking harness, check intermediate connector A-13, and repair if necessary.

  • Check power supply line for damage.

Q. Is the check result normal?

Go to Step 17 .
Repair the damaged harness wire.

STEP 17. Connector check: B-29 engine-ECU connector


Q. Is the check result normal?

Go to Step 18 .
Repair or replace the connector.

STEP 18. Check harness between B-105 (terminal No. 2) No. 2 injector connector and B-29 (terminal No. 18) engine-ECU connector.



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

Q. Is the check result normal?

Go to Step 19 .
Repair the damaged harness wire.

STEP 19. Perform signal wave pattern measurement at B-29 engine-ECU connector (Using an oscilloscope).



  • Disconnect engine-ECU connector, and connect special tool power plant ECU check harness (MB992110) to measure at connector for inspection.
  • Engine: Idling
  • Transmission: Neutral <M/T> or P range <CVT>
  • Voltage between terminal No. 18 and earth.
OK: Waveforms should be displayed on inspection procedure using an oscilloscope (Refer to ).

Q. Is the check result normal?

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