Variable Induction Control Module: Testing and Inspection

Intake Manifold Flap Vacuum Actuator, Checking

• The test must only be performed if torque loss is present, meaning if there is reduced elasticity or reduced engine acceleration.

Special tools, testers and auxiliary items required

• Hand Vacuum Pump (VAS 6213) or Hand Vacuum Pump (V.A.G 1390)

Conditions

• Intake Manifold Tuning (IMT) valve (N156) was checked using the "Guided Fault Finding" in the vehicle diagnostic tester.

Sequence

If the IMT valve is OK:

- Start engine and let run at idle.

- Have a 2nd person increase engine speed abruptly (press accelerator pedal). Observe variable intake manifold vacuum actuator.






• The actuator must switch.

If change over does not function as specified:

- Check whether the vacuum system, including the vacuum reservoir in intake manifold, is properly sealed.

- Check whether the change over mechanism moves easily. Do this by actuating the linkage by hand.

- Check whether the vacuum lines are correctly connected.

- Check that vacuum hoses are not porous.

If no malfunction was found:

- Remove the air filter. Refer to => [ Air Filter Housing Overview ] Service and Repair.

- Disconnect the vacuum hose at the vacuum actuator.

- Connect the (VAS 6213) to the vacuum actuator.






- Set the slide ring - 1 - on Hand Vacuum Pump (VAS 6213) to position - A - for "vacuum".






- Operate the (VAS 6213) several times.

• The operating plunger must move.

- Disconnect the (VAS 6213) from the vacuum actuator.

• Operating the plunger must spring back into its initial position.

If the operating plunger does not move as described:

- Replace the vacuum actuator.