Code No. P0402: EGR Flow Excessive

OPERATION

Refer to Code No. P0102: Air Flow Sensor Circuit Low Input .
Refer to Code No. P0403: EGR Valve DC Motor Malfunction .
Refer to Code No. P0489: EGR Valve Position Sensor Circuit Low Input .

FUNCTION

The engine-ECU monitors the EGR flow rate.

TROUBLE JUDGEMENT

Check Condition

The amount of fuel consumption, the engine speed, the target lambda, the gear position, the vehicle speed, the intake air temperature and the atmospheric pressure are within the threshold values.

Judgement Criterion

The EGR flow rate is higher than the specified value.

FAIL-SAFE AND BACKUP FUNCTION

The small injection quantity learning is prohibited.
The DPF regeneration is prohibited.
The NPG/SPG control is stopped.
The EGR control is stopped (fully closed).

PROBABLE CAUSES

Failed EGR passage (air suction)
Failed connector or harness damage of EGR valve system
Failed EGR valve operation
Failed connector or harness damage of AFS system
Failed AFS (abnormal output characteristics)
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q. Is diagnosis code P0403 or P2413 set?

	Inspection chart for diagnosis codes (Refer to ).

	Go to Step 2.

STEP 2. Check of damage in EGR+ line between EGR valve assembly connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 3.

	Repair the connector(s) or wiring harness.

STEP 3. Check of damage in EGR- line between EGR valve assembly connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 4.

	Repair the connector(s) or wiring harness.

STEP 4. Check of damage in EGRE line between EGR valve assembly connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 5.

	Repair the connector(s) or wiring harness.

STEP 5. Check of damage in EGR5 line between EGR valve assembly connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 6.

	Repair the connector(s) or wiring harness.

STEP 6. Check of damage in EGRP line between EGR valve assembly connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 7.

	Repair the connector(s) or wiring harness.

STEP 7. Check EGR valve itself.

Check EGR valve itself [Refer to GROUP 17 - Emission Control <DIESEL> - Exhaust Gas Recirculation (EGR) System - EGR Valve (DC motor) Check ].

Q. Is the check result normal?

	Go to Step 8.

	Replace the EGR valve assembly.

STEP 8. Check EGR passage for air suction.

Check the EGR valve, the EGR valve pipe and the EGR cooler for the air suction.

Q. Is the check result normal?

	Go to Step 9.

	Cleaning or replace the EGR valve, EGR valve pipe and EGR cooler.

STEP 9. Check of damage in AFSE&ECBE line between air flow sensor connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 10.

	Repair the connector(s) or wiring harness.

STEP 10. Check of damage in AFS line between air flow sensor connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 11.

	Repair the connector(s) or wiring harness.

STEP 11. Replace the air flow sensor.

After replacing the air flow sensor, re-check the trouble symptoms.

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.