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 Conditions

The engine speed is less than 8, 000 r/min.
Not during the fuel cut and the forced injector driving (actuator test).
Throttle position sensor (main) output is less than 5.0 V.

Judgment Criterion

Surge voltage of injector coil is not detected for 2 seconds.

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 03: 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-44 intermediate connector

Q. Is the check result normal?

	Go to Step 3 .

	Repair or replace the connector.

STEP 3. Perform voltage measurement at B-44 intermediate connector.

Disconnect connector, and measure at female connector side.
Ignition switch: ON
Voltage between terminal No. 6 and earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 13 .

	Go to Step 4 .

STEP 4. Connector check: A-24X injector relay connector

Q. Is the check result normal?

	Go to Step 5 .

	Repair or replace the connector.

STEP 5. Check injector relay itself.

Check injector relay itself (Refer to ).

Q. Is the check result normal?

	Go to Step 6 .

	Replace the injector relay.

STEP 6. Perform resistance measurement at A-24X injector relay connector.

Remove relay and measure at relay box side.
Resistance between terminal No. 2 and earth.

OK: Continuity (2 Ω or less)

Q. Is the check result normal?

	Go to Step 7 .

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

Remove relay and measure at relay box side.
Ignition switch: ON
Voltage between terminal No. 1 and earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 9 .

	Go to Step 8 .

STEP 8. 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) injector relay connector. Check power supply line for open/short circuit.

	Repair or replace the connector.

STEP 9. Perform voltage measurement at A-24X injector relay connector.

Remove relay and measure at relay box side.
Ignition switch: ON
Voltage between terminal No. 4 and earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 11 .

	Go to Step 10 .

STEP 10. 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) injector relay connector. Check power supply line for open/short circuit.

	Repair or replace the connector.

STEP 11. Check harness between A-24X (terminal No. 3) injector relay connector and B-44 (terminal No. 6) intermediate 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 12 .

	Repair the damaged harness wire.

STEP 12. 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) injector relay connector. Check power supply line for damage.

	Repair or replace the connector.

STEP 13. Check No. 3 injector itself.

Check No. 3 injector itself (Refer to ).

Q. Is the check result normal?

	Go to Step 14 .

	Replace the No. 3 injector.

STEP 14. Connector check: A-33X engine control relay connector and A-24X injector relay connector

Q. Are the check results 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) injector 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-44 (terminal No. 6) intermediate 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. 3 injector connector and B-29 (terminal No. 18) engine-ECU connector.

note

Before checking harness, check intermediate connector B-44, and repair if necessary.

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. Check harness between B-44 (terminal No. 6) intermediate connector and B-105 (terminal No. 1) No. 3 injector connector.

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

Q. Is the check result normal?

	Go to Step 20 .

	Repair the damaged harness wire.

STEP 20. 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: P range
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.