Fuel System, Bleeding

Fuel System, Bleeding

• To prevent damage to catalytic converter, the fuel system without return line must be bled after repair work on fuel lines or on fuel filter. The vehicle must only be started after bleeding it first.

• Pay attention to the rules of cleanliness. Refer to => [ Clean Working Conditions ] Fuel Supply.

Special tools, testers and auxiliary items required

• Suction Pump (VAS 5226)

• Adapter for K-jetronic Test Device (V.A.G 1318/20)


The fuel system is under pressure! Wear protective goggles and protective clothing to prevent injuries and contact with skin. Before disconnecting the connection, wrap a cloth around the connection. Then release pressure by carefully disconnecting the connection.

- Remove the cap => [ (Item 9) Cap ] Service and Repair from breather valve => [ (Item 8) Breather Valve ] Service and Repair.

- Turn valve on T piece - arrow - counterclockwise until completely open.






- Install the (V.A.G 1318/20-1) onto the (V.A.G 1318/20).

- Install the (V.A.G 1318/20) onto the pressure valve, tightening by hand.

- Connect the hose from the (VAS 5226) as illustrated.






- Turn the valve (on the (V.A.G 1318/20) ) clockwise into the valve until it stops.

- Check the (V.A.G 1318/20) and hose connections for leaks.

• Fuel pump function is checked via output Diagnostic Test Mode (DTM).

• The engine must be started briefly before the output DTM can be performed a second time.

- Connect the vehicle diagnostic tester - 1 - as follows:






- Connect the diagnostic cable - 2 - connector to the Data Link Connector (DLC) in the driver's footwell.

- Turn on the ignition.

- Press the Vehicle Self-Diagnosis, On Board Diagnostic (OBD), Engine Electronics and Output Diagnostic Test Mode buttons.

- Press the right arrow button => repeatedly until the fuel pump relay (J17) is activated. This activates the fuel pump.

- Complete the output DTM and turn off the ignition when the fuel begins to flow out of the valve without any bubbles in it.

- On the (V.A.G 1318/20) , turn the valve - arrow - counterclockwise until completely open.






- Clamp off the hose from the (VAS 5226) (for example, with (3094) ) and pull the hose off from the (V.A.G 1318/20-1).

- Remove the (V.A.G 1318/20) from the pressure valve.

- Install the cap => [ (Item 9) Cap ] Service and Repair on breather valve.