P0490 – EGR Valve Position Sensor Circuit High Input Euro5b MMC L200 IV

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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. 71) and earthed to the engine-ECU (terminal No. 81) from the EGR valve assembly (terminal No. 2).

The sensor signal is inputted to the engine-ECU (terminal No. 57) from the EGR valve assembly output terminal (terminal No. 1).

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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.

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TROUBLE JUDGMENT

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.

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

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PROBABLE CAUSES

Failed EGR valve position sensor

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

Failed engine-ECU

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DIAGNOSIS PROCEDURE

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

Item 16: EGR valve position sensor

Q. Is the check result normal?

STEP 2. Connector check: A-45 EGR valve assembly connector

Q. Is the check result normal?

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

Disconnect connector, and measure at harness side.

Resistance between terminal No. 2 and earth.

Q. Is the check result normal?

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

Q. Is the check result normal?

STEP 5. Check harness between A-45 (terminal No. 2) EGR valve assembly connector and C-105 (terminal No. 81) engine-ECU connector.

Check earthing line for open circuit.

Q. Is the check result normal?

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

Item 16: EGR valve position sensor

Q. Is the check result normal?

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

Item 16: EGR valve position sensor

Q. Is the check result normal?