Checking function

• Start engine and run at idling speed.
• Switch off ignition.
• Observe position of lever on Intake Manifold Flap Change-over Valve N239 (2nd technician required).
• The intake manifold flap must, after switching off ignition, close and after approx. 3 seconds open again.

If change-over does not occur, the following checks must be carried out.

• Check intake manifold flap change-over mechanics for freedom of movement. To do this operate rods by hand.

Fig 1: V.A.G 1390 Connected To Vacuum Unit

Courtesy of VOLKSWAGEN UNITED STATES, INC.

• Pull vacuum hose off vacuum unit - 1  -.
• Connect hand vacuum pump VAG1390 to vacuum unit.
• Operate hand vacuum pump and check intake manifold flap changeover mechanism for ease of movement and operation.
• Check vacuum lines for correct connection.

If no fault is found in the mechanical components:

• Check intake manifold flap change-over valve.