EXHAUST GAS RECIRCULATION VALVE (STEPPER MOTOR) CHECK



CHECKING THE OPERATION SOUND



1.Check that the operation sound of the stepper motor can be heard from the exhaust gas recirculation valve when the power supply mode of the electric motor switch is ACC.
2.If the operation sound cannot be heard, inspect the drive circuit of the stepper motor.
note If the circuit is normal, either the stepper motor or the engine-ECU may have failed.

CHECKING THE COIL RESISTANCE



1.Disconnect the exhaust gas recirculation valve connector.
2.Measure the resistance between terminal No. 2 and either terminal No. 1 or terminal No. 3 of the connector at the exhaust gas recirculation valve.
Standard value: 20 - 24 Ω (at 20°C)
3.Measure the resistance between terminal No. 5 and either terminal No. 4 or terminal No. 6 of the connector at the exhaust gas recirculation valve.
Standard value: 20 - 24 Ω (at 20°C)
4.If the value deviates from the standard value, replace the exhaust gas recirculation valve.

OPERATION CHECK



1.Remove the exhaust gas recirculation valve.
2.Attach a special tool test harness (MB991658) to the connector at the exhaust gas recirculation valve.

3.
caution Connecting battery voltage to the exhaust gas recirculation valve for a long term could damage the coil.
Connect the positive (+) terminal of the battery to terminal No. 2.
4.Connect terminals No. 1 and No. 3 to the negative (-) terminal of the battery, in order to test whether the stepper motor vibrates (with a slight shudder), indicating that the stepper motor is operating.

5.
caution Connecting battery voltage to the exhaust gas recirculation valve for a long term could damage the coil.
Connect the positive (+) terminal of the battery to terminal No. 5.
6.Connect terminals No. 4 and No. 6 to the negative (-) terminal of the battery, in order to test whether the stepper motor vibrates (with a slight shudder), indicating that the stepper motor is operating.
7.If a vibration can be felt during the test, the stepper motor is normal.
8.Using a new gasket, install the exhaust gas recirculation valve by tightening its mounting bolts to the specified torque.
Tightening Torque:

    24 ± 3 N·m