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The article below describes how I replaced the Throttle Bypass Valve (also known as Dump Valve) on my own Audi S2. This procedure was performed on a UK vehicle and therefore this should be remembered if attempting this on your own car.

No responsisbilty is accepted for anyone attempting this procedure by following the steps contained in these pages. This is intended as a guide only and all usual precautions should be heeded when attempting work on a motor vehicle. I cannot be held responsible for any damage sustained as a result of using these pages.

Tools needed are as follows:

1. #1 Phillips (cross) headed screwdriver
2. Flat bladed screw driver
3. 6mm socket (possible) with ratchet and extension bars
3. Replacement Throttle Bypass Valve (Audi Part number 034 145 710 B)

First step is to raise the bonnet of the car. You may want to consider disconnecting the battery. When the bonnet is open, the courtesy light in the boot comes on. Disconnecting the battery will prevent the current drain. An alternative is to pull fuse #4 from the fusebox.

Upon raising the bonnet you will have the view seen here on the left.
The 4 screws arrowed on the illustration should be removed using tool #1.

With screw #4 released,the lower trim piece
below the headlamp can be pulled out of the
way. The piece can be removed completely but
on my car it was very difficult to remove.
Rather than risk breaking it, I moved it down
below theheadlamp washer out the way. The two
lower headlamp screws arrowed here should now
be removed, again using tool #1.

The headlmap is now free to be removed.
Be careful not to break any lugs during removal.
The base of the lamp will catch slightly on the
bumper so it has to be angled to extract it.
There are two wiring cluster on the back of the lamp.
These should be disconnected completely and the unit
should be placed to one side. The plastic trim piece
marked here should slide up to be removed.

The valve is arrowed (#1) here with each securing clip
arrowed (2,3 and 4). Note that the valve has been catching
on a plastic trim piece underneath (5). To make things easier
it is recommended to remove this part. It slides up to the top,
although you have to push the T-piece and attached hoses out of
way. This will allow you to lift the hose from below which will
help when fitting the new valve.
The clips (3 and 4) should be removed using a flat blade screwdriver
if possible. It may be necessary to use the 6mm socket to start them
moving first. The small clip which secures the small flexible tube
should be widened before attempting to remove. I was unable to remove
this clip and the new valve has been fitted with no securing clip.

With clip 4 from the previous picture loosened,
it is possible to free the valve from the pipe
on that side. With that done, it is then a case
of lifting the valve up the way to free the pipe
from clip 3. The small flexible tube can then be

With the old valve off it is then a reversal of
removal as the great Haynes manual always tells you.
The new valve can be seen here on the right.