Code No. P0490: Exhaust Gas Recirculation Valve (stepper motor) Circuit Malfunction (battery short)

OPERATION

Power is supplied to the exhaust gas recirculation valve connector terminal from the engine control relay connector terminal.
The engine-ECU connector terminal EGRA, EGRB, EGRC and EGRD makes the power transistor in the unit be in ON position, and that makes currents go on the exhaust gas recirculation valve connector terminal.

FUNCTION

In response to the signal from the engine-ECU, the exhaust gas recirculation valve (stepper motor) controls a flow rate of exhaust gas recirculation.

TROUBLE JUDGEMENT

Check Conditions

Ignition switch is "ON" position.
Battery positive voltage is more than 10 V and is less than 16.5 V.

Judgement Criterion

When the exhaust gas recirculation valve is energised, the engine-ECU voltage is more than 6.7 V for 1.4 seconds.

PROBABLE CAUSES

Failed exhaust gas recirculation valve (stepper motor)
Short circuit in exhaust gas recirculation valve circuit or loose connector contact
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check of short circuit to power supply in EGRA, EGRB, EGRC, EGRD line between exhaust gas recirculation valve connector and engine-ECU connector.

Q. Is the check result normal?

	Go to Step 2.

	Repair the connector(s) or wiring harness.

STEP 2. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is the diagnosis code stored?

	Replace the engine-ECU.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).