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 JUDGMENT

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.

Judgment Criterion

The EGR flow rate is higher than the specified value.

FAIL-SAFE AND BACKUP FUNCTION

None

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

DIAGNOSTIC PROCEDURE

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

Q. Is the diagnosis code P0403 or P2413 output?

	Inspection chart for diagnosis codes (Refer to ).

	Go to Step 2 .

STEP 2. Connector check: B-41 EGR valve assembly connector

Q. Is the check result normal?

	Go to Step 3 .

	Repair or replace the connector.

STEP 3. Connector check: B-39 and B-40 engine-ECU connectors

Q. Is the check result normal?

	Go to Step 4 .

	Repair or replace the connector.

STEP 4. Check harness between B-40 (terminal No. 115) engine-ECU connector and B-41 (terminal No. 6) EGR valve assembly connector.

note

Before checking harness, check intermediate connector A-11, and repair if necessary.

Check output line for damage.

Q. Is the check result normal?

	Go to Step 5 .

	Repair the damaged harness wire.

STEP 5. Check harness between B-40 (terminal No. 130) engine-ECU connector and B-41 (terminal No. 4) EGR valve assembly connector.

note

Before checking harness, check intermediate connector A-11, and repair if necessary.

Check output line for damage.

Q. Is the check result normal?

	Go to Step 6 .

	Repair the damaged harness wire.

STEP 6. Check harness between B-39 (terminal No. 81) engine-ECU connector and B-41 (terminal No. 2) EGR valve assembly connector.

Check earthing line for damage.

Q. Is the check result normal?

	Go to Step 7 .

	Repair the damaged harness wire.

STEP 7. Check harness between B-39 (terminal No. 71) engine-ECU connector and B-41 (terminal No. 3) EGR valve assembly connector.

Check power supply line for damage.

Q. Is the check result normal?

	Go to Step 8 .

	Repair the damaged harness wire.

STEP 8. Check harness between B-39 (terminal No. 57) engine-ECU connector and B-41 (terminal No. 1) EGR valve assembly connector.

Check output line for damage.

Q. Is the check result normal?

	Go to Step 9 .

	Repair the damaged harness wire.

STEP 9. Check EGR valve itself.

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

Q. Is the check result normal?

	Go to Step 10 .

	Replace the EGR valve assembly.

STEP 10. 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 11 .

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

STEP 11. Connector check: A-06 air flow sensor connector

Q. Is the check result normal?

	Go to Step 12 .

	Repair or replace the connector.

STEP 12. Check harness between A-06 (terminal No. 2) air flow sensor connector and B-40 (terminal No. 155) engine-ECU connector.

Check earthing line for damage.

Q. Is the check result normal?

	Go to Step 13 .

	Repair the damaged harness wire.

STEP 13. Check harness between A-06 (terminal No. 1) air flow sensor connector and B-40 (terminal No. 140) engine-ECU connector.

Check output line for damage.

Q. Is the check result normal?

	Go to Step 14 .

	Repair the damaged harness wire.

STEP 14. 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.