Code No. P0403: Exhaust Gas Recirculation Control System

OPERATION

Power is supplied to the exhaust gas recirculation valve (terminal No. 2 and No. 5) from the engine control relay (terminal No. 1).
The engine-ECU <M/T> or engine-A/T-ECU <A/T> (terminal No. 3, No. 12, No. 19 and No. 26) makes the power transistor in the unit be in "ON", and that makes currents go on the exhaust gas recirculation valve (terminal No. 1, No. 3, No. 4 and No. 6).

FUNCTION

Based on the signal from engine-ECU <M/T> or engine-A/T-ECU <A/T>, the exhaust gas recirculation valve (stepper motor) controls the exhaust gas recirculation rate.

TROUBLE JUDGMENT

Check Conditions

Battery positive voltage is 10.3 V or higher.
When the ignition switch is turned to ON position from OFF position.

Judgment Criterion

The exhaust gas recirculation valve motor coil surge voltage (battery positive voltage +2 V) is not detected for 3 seconds.

Check Conditions

Battery positive voltage is 10.3 V or higher.
The exhaust gas recirculation valve is in operation after the engine starting process is completed.

Judgment Criterion

The exhaust gas recirculation valve motor coil surge voltage (battery voltage +2 V) is not detected for 30 seconds.

PROBABLE CAUSES

Failed exhaust gas recirculation valve
Open/short circuit in exhaust gas recirculation valve circuit or loose connector contact
Failed engine-ECU <M/T> or engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-02 exhaust gas recirculation valve connector

Q. Is the check result normal?

	Go to Step 2 .

	Repair or replace the connector.

STEP 2. Check exhaust gas recirculation valve itself.

Check exhaust gas recirculation control solenoid valve itself [Refer to GROUP 17 - Emission Control System <6G7> - Exhaust Gas Recirculation System - Exhaust Gas Recirculation Valve (stepper motor) Check .

Q. Is the check result normal?

	Go to Step 3 .

	Replace the exhaust gas recirculation valve (stepper motor).

STEP 3. Perform voltage measurement at B-02 exhaust gas recirculation valve connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal No. 2, No. 5 and earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 5 .

	Go to Step 4 .

STEP 4. Connector check: B-15X engine control relay connector

Q. Is the check result normal?

	Check and repair harness between B-02 (terminal No. 2, No. 5) exhaust gas recirculation valve connector and B-15X (terminal No. 1) engine control relay connector. Check power supply line for open/short circuit.

	Repair or replace the connector.

STEP 5. Perform voltage measurement at D-243 engine-ECU <M/T> connector or D-212 engine-A/T-ECU <A/T> connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal No. 3, No. 12, No. 19, No. 26 and earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 7 .

	Go to Step 6 .

STEP 6. Connector check: D-243 engine-ECU <M/T> connector or D-212 engine-A/T-ECU <A/T> connector

Q. Is the check result normal?

Check harness between B-02 (terminal No. 1) exhaust gas recirculation valve and D-243 (terminal No. 3) engine-ECU <M/T> connector or D-212 (terminal No. 3) engine-A/T-ECU <A/T> connector
Check harness between B-02 (terminal No. 3) exhaust gas recirculation valve and D-243 (terminal No. 12) engine-ECU <M/T> connector or D-212 (terminal No. 12) engine-A/T-ECU <A/T> connector
Check harness between B-02 (terminal No. 4) exhaust gas recirculation valve and D-243 (terminal No. 19) engine-ECU <M/T> connector or D-212 (terminal No. 19) engine-A/T-ECU <A/T> connector
Check harness between B-02 (terminal No. 6) exhaust gas recirculation valve and D-243 (terminal No. 26) engine-ECU <M/T> connector or D-212 (terminal No. 26) engine-A/T-ECU <A/T> connector

Check power supply line for open/short circuit.

	Repair or replace the connector.

STEP 7. Connector check: D-243 engine-ECU <M/T> connector or D-212 engine-A/T-ECU <A/T> connector

Q. Is the check result normal?

	Go to Step 8 .

	Repair or replace the connector.

STEP 8. Check harness between B-02 exhaust gas recirculation valve connector and D-243 engine-ECU <M/T> connector or D-212 engine-A/T-ECU <A/T> connector.

Check harness between B-02 (terminal No. 1) exhaust gas recirculation valve and D-243 (terminal No. 3) engine-ECU <M/T> connector or D-212 (terminal No. 3) engine-A/T-ECU <A/T> connector
Check harness between B-02 (terminal No. 3) exhaust gas recirculation valve and D-243 (terminal No. 12) engine-ECU <M/T> connector or D-212 (terminal No. 12) engine-A/T-ECU <A/T> connector
Check harness between B-02 (terminal No. 4) exhaust gas recirculation valve and D-243 (terminal No. 19) engine-ECU <M/T> connector or D-212 (terminal No. 19) engine-A/T-ECU <A/T> connector
Check harness between B-02 (terminal No. 6) exhaust gas recirculation valve and D-243 (terminal No. 26) engine-ECU <M/T> connector or D-212 (terminal No. 26) engine-A/T-ECU <A/T> connector

Check output line for damage.

Q. Are the check results normal?

	Go to Step 9 .

	Repair the damaged harness wire.

STEP 9. Check harness between B-02 (terminal No. 2, No. 5) exhaust gas recirculation valve connector and B-15X (terminal No. 1) engine control relay connector.

Check power supply line for damage.

Q. Is the check result normal?

	Replace the engine-ECU <M/T> or engine-A/T-ECU <A/T>.

	Repair the damaged harness wire.