)
- Check that the operation sound of the stepper motor can be heard from the EGR valve when the ignition switch is turned ON (without starting the engine).
- 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-A/T-ECU may have failed.
)
- Remove the EGR valve.
- Measure the resistance between terminal No. 2 and either terminal No. 1 or terminal No. 3 of the connector at the EGR valve.
Standard value: 20 -
24 Ω
(at 20°C )
- Measure the resistance between terminal No. 5 and either terminal No. 6 or terminal
No. 4 of the connector at the EGR valve.
Standard value: 20 - 24 Ω (atUsing a new gasket, install the EGR valve by tightening its mounting bolts to the specified torque.20°C )
Tightening Torque: 24 ±
4 N·m
)
- Remove the EGR valve.
- Attach a test wiring harness (special tool MB991658) to the connector at the EGR valve.
)
- Connect the positive (+) terminal of the battery to terminal No. 2.
CAUTION- 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.
CAUTION)
- Connect the positive (+) terminal of the battery to terminal No. 5.
- 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.
- If a vibration can be felt during the test, the stepper motor is normal.
- Using a new gasket, install the EGR valve by tightening its mounting bolts to the specified torque.
Tightening torque: 24 ±
3 N·m
Cleaning the EGR Valve
- Remove the EGR valve and check that the EGR valve is not stuck or clogged with carbon deposits. Use a wire brush to clean the valve if necessary.
CAUTION- Using a new gasket, install the EGR valve by tightening its mounting bolts to the specified torque.
Tightening torque: 24 ±
3 N·m