Volkswagen Workshop Service and Repair Manuals

At low engine speeds the vacuum in the intake manifold is not sufficient to ensure correct functioning of the exhaust gas recirculation system. Therefore to increase vacuum the throttle valve remains closed up to 2200 rpm after starting the engine.

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

• ◆ Hand vacuum pump V.A.G 1390
• ◆ V.A.G 1331 Torque wrench (5...50 Nm)

Removing

• ‒ → Remove intake hose -1-.
• ‒ Pull vacuum hose -6- off vacuum unit -5-.
• ‒ Unscrew securing bolts -2- and remove throttle valve housing -3- with O ring -4-.

Installing

• ‒ Attach throttle valve housing with O ring to intake manifold and tighten securing bolts to
       10 Nm.

Note:

Renew O ring if damaged.

• ‒ Attach vacuum hose -6- and install intake hose -1-.

Functional check of vacuum unit

• ‒ → Connect vacuum pump V.A.G 1390 to vacuum unit -1- and create a vacuum.

Specification:
     The throttle valve must close up to stop and remain closed.

If the specification is not attained:

• ‒ Renew vacuum unit.