Code No. P0403: Exhaust Gas Recirculation Valve (DC Motor) Malfunction

OPERATION

System power is supplied from the engine-ECU (terminal No. 19) to the exhaust gas recirculation valve (terminal No. 6).
The engine-ECU (terminal No. 20) turns on the power transistor to flow current to the exhaust gas recirculation valve (terminal No. 4).

FUNCTION

The engine-ECU performs duty control over the exhaust gas recirculation valve (DC motor).
The engine-ECU performs feedback control over the exhaust gas recirculation valve based on the signals from the exhaust gas recirculation position sensor.

TROUBLE JUDGMENT

Check Condition

Ignition switch is in "ON" position

Judgment Criterion

An over current cut-off signal from the exhaust gas recirculation valve drive control integrated circuit (IC) is detected.

PROBABLE CAUSES

Failed exhaust gas recirculation valve
Open/short circuit in exhaust gas recirculation valve circuit or loose connector contact
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-02 exhaust gas recirculation valve assembly 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 valve itself [Refer to GROUP 17 - Exhaust Gas Recirculation System - Exhaust Gas Recirculation Valve (DC motor) Check ].

Q. Is the check result normal?

	Go to Step 3.

	Replace the exhaust gas recirculation valve assembly.

STEP 3. Connector check: D-213 engine-ECU connector.

Q. Is the check result normal?

	Go to Step 4.

	Repair or replace the connector.

STEP 4. Check harness between the D-213 (terminal No. 19) engine-ECU connector and B-02 (terminal No. 6) exhaust gas recirculation valve assembly connector.

Check output line for open/short circuit and damage.

Q. Is the check result normal?

	Go to Step 5.

	Repair the damaged harness wire.

STEP 5. Check harness between D-213 (terminal No. 20) engine-ECU connector and B-02 (terminal No. 4) exhaust gas recirculation valve connector.

Check output line for open/short circuit and damage.

Q. Is the check result normal?

	Go to Step 6.

	Repair the damaged harness wire.

STEP 6. M.U.T.-III diagnosis code

After clearing the diagnosis code through M.U.T.-III, start the engine and confirm whether the diagnosis code is set.

Q. Is the diagnosis code set?

	Replace the engine-ECU. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - Precautions Before Service - How to Perform Chassis Number Writing ). After replacing the engine-ECU, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).

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