Code No. P0490: EGR Valve Position Sensor Circuit High Input

OPERATION

A power voltage of 5 V is applied to the EGR valve assembly power terminal from the engine-ECU connector terminal EGR5 and earthed to the engine-ECU connector terminal EGRE from the EGR valve assembly connector terminal.
The sensor signal is inputted to the engine-ECU connector terminal EGRP from the EGR valve assembly output terminal.

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.

FAIL-SAFE AND BACKUP FUNCTION

The DPF regeneration is prohibited.
The throttle valve is opened (Electrical discontinuity).
The EGR control is stopped (fully closed).
The AS&G control is prohibited.

PROBABLE CAUSES

Failed EGR valve position sensor
Open circuit or harness damage 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. Perform resistance measurement at EGR valve assembly connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Resistance between terminal engine-ECU EGRE line and body earth.

OK: Continuity (2 Ω or less)

Q. Is the check result normal?

	Go to Step 5.

	Go to Step 3.

STEP 3. Check harness between EGR valve assembly connector terminal and engine-ECU connector terminal EGRE.

Check earthing line for open circuit and damage.

Q. Is the check result normal?

	Go to Step 4.

	Repair or replace the connector, or repair the damaged harness wire.

STEP 4. 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.

STEP 5. 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.