Volkswagen Workshop Service and Repair Manuals

Operation

Vehicles for Switzerland and Sweden are equipped with an exhaust gas recirculation valve.

The EGR valve is a one-stage valve. It functions according to temperature and pressure.

Above approx. 61 °C exhaust gas is recirculated continuously, except at idling or at full throttle. At temperatures below 45 °C thermo-pneumatic valve interrupts vacuum supply and EGR valve closes.

Checking the EGR Valve

• ◆ Engine oil temperature at least 80 °C

Engines with DIS only

• ‒ → Remove connectors from DIS unit and join them together.

Continuation for all vehicles

• ‒ Start engine and run at idling.

• ‒ → Detach vacuum hose -1- from vacuum connection -2-.
• ‒ Detach vacuum hose -3- from thermo-pneumatic valve -4- and connect to free vacuum connection -2-. The idling should deteriorate (shaking) or the engine should stall.
• ‒ Should idling not deteriorate, detach EGR pipe -5- and repeat test.

Idling now deteriorates:

• ‒ → Clean clogged EGR passage in exhaust manifold with 4 mm drill -arrow-.

Idling does not deteriorate:

• ‒ Renew EGR valve.

→ Testing thermo-pneumatic valve

• ‒ Remove thermo-pneumatic valve -4- and heat and/or cool in water.
• ‒ Blow through valve:
• ‒ Below approx. + 45 °C it should be closed
• ‒ Above approx. 61 °C it should be open

• ‒ → Install valve and connect vacuum pipe. Vacuum pipe -6- from throttle valve housing to angled connection -arrow-.