Code No. P0406: EGR Valve Position Sensor Circuit High Input

OPERATION

A power voltage of 5 V is applied to the EGR valve assembly power terminal (terminal No. 3) from the engine-ECU (terminal No. 80) and earthed to the engine-ECU (terminal No. 72) from the EGR valve assembly (terminal No. 2).
The sensor signal is inputted to the engine-ECU (terminal No. 51) from the EGR valve assembly output terminal (terminal No. 1).

FUNCTION

The EGR valve assembly detects the position of the EGR valve and sends the signal to the engine-ECU.
Based on the signal, the engine-ECU performs the feedback control of the EGR valve.

TROUBLE JUDGMENT

Check Conditions

Battery positive voltage is 8 - 16 V
2 seconds later after the ignition switch has been in "ON" position or the engine has started up.

Judgment Criterion

The EGR valve position sensor output voltage is 4.80 V or more for 0.5 second.

PROBABLE CAUSES

Failed EGR valve position sensor
Open circuit in EGR valve position sensor circuit or loose connector contact

Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

Refer to Data List Reference Table .

Item 16: EGR valve position sensor

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: A-45 EGR valve assembly connector

Q. Is the check result normal?

Go to Step 3 .

Repair or replace the connector.

STEP 3. Perform resistance measurement at A-45 EGR valve assembly connector.

Disconnect and measure at harness side.
Ignition switch: ON
Resistance between terminal No. 2 and earth.

OK: Continuity (2 Ω or less)

Q. Is the check result normal?

Go to Step 7 .

Go to Step 4 .

STEP 4. Connector check: C-105 engine-ECU connector

Q. Is the check result normal?

Go to Step 7 .

Repair or replace the connector.

STEP 5. Check harness between A-45 (terminal No. 2) EGR valve assembly connector and C-105 (terminal No. 72) engine-ECU connector.

Check earthing line for open circuit.

Q. Is the check result normal?

Go to Step 6 .

Repair the damaged harness wire.

STEP 6. M.U.T.-III data list

Refer to Data List Reference Table .

Item 16: EGR valve position sensor

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. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - 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 ).

STEP 7. M.U.T.-III data list

Refer to Data List Reference Table .

Item 16: EGR valve position sensor

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 EGR valve assembly.