SEAT Workshop Service and Repair Manuals

Perform check only if performance is poor.

The intake manifold change-over from long to short intake ports occurs at approx. 4 500 rpm.

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required

• ◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
• ◆ → Hand vacuum pump V.A.G 1390

Checking function

• ‒ Start engine and run at idling speed.

The actuating element (vacuum unit) on the intake manifold holds the change-over shaft in the long intake port position.

• ‒ Have a second person press accelerator pedal to stop (throttle burst). Observe vacuum reservoir for intake manifold change-over (location: on intake manifold, left).

• ‒ → The actuating element must rotate the barrel in the intake manifold (arrow) at about 4 500 rpm.

If the positioning element does not perform the change-over sequence:

• ‒ Switch off ignition.
• ‒ First check the activation of the intake manifold change-over valve (N156) via final control diagnosis =>Page 01-89.

If the activation is OK:

• ‒ → Pull vacuum hose off non-return valve -1-.
• ‒ Connect hand vacuum pump V.A.G 1390 to non-return valve -1-.

Note:

The final control diagnosis is shut off after a minute. If the final control diagnosis must be repeated, the engine must be briefly restarted.

• ‒ → Perform final control diagnosis again. When the intake manifold change-over valve is activated, operate the hand pump uniformly.
      The positioning element must switch back and forth between
      the two positions.

If the change-over does not function as described:

• ‒ Check the change-over mechanical components for ease of movement. Move the rods by hand.
• ‒ Check the vacuum hoses are connected correctly.
• ‒ Check the vacuum system including the vacuum reservoir.

Note:

The vacuum reservoir is bolted below the intake manifold.