Small Bore pipe under rear seats???

[Crawford_S2]

Thats the first time i ever saw the battery under the back seat. I've got a 3B and i've never seen the battery in a ABY. I had my back seat out on thursday to run new power cables and speaker wires, I also found that hose after the audi dealer said that the ECU was in the passenger footwell. Just shows that some Dealers don't have a CLUE!

Eh..... ECU is in the passenger footwell dude! That module by the battery does something else but it ain't the ECU for the motor. For a full explaination i should know what it does but i don't sorry

[4WheelDrifter]

On a 3B the ABS ECU is under the seat, as is the Servotronic ECU.

[Davidsinclair05]

Sorry your right, but the dealer said that the vacuum pipe connects into a module and then sends the data to the ECU, I just assumed that the box to the right was the ECU, if the ECU is in the footwell why do the pipoes run all the way to the backseats and then forward again?

[4WheelDrifter]

The ECUs under the rear seat are independent of the Motronic engine ECU. The Motronic ECU just has one hose going to it, for the MAP sensor.

[Davidsinclair05]

Is that the one that connects to the inlet manifold?

[Davidsinclair05]

or am i in the right place under the backseat?

[4WheelDrifter]

Both vacuum hoses lead to and from the inlet manifold, but not to each other.

[Dpicariello]

Didn't you notice your difflock wasn't working Dan?

Nope, heard something actuate whenever I pressed the button (assumed it was working) but to be honest I've never had to actually use it.

[S2central.net]

The actuator won't move unless vacuum pressure is presented to the difflock controller. You might have heard internals on the controller clicking - but it won't have moved the diflock mechanism itself.

[S2 EDS]

What a really interesting post. My Diff Lock button in the tray does not seem to come on and am wondering if I have the same prob - that said I have not nailed my car to note boost probs. That said - rear bench is coming out in the morning and will see if my diff lock actuator has come loose - not heard any hissing myself.

[newsh]

What an excellent place this forum is, I was just wanting a pic of the battery box and this old thread popped up! Spooky eh?

Mine below..

[UrS4boy]

Rear Diff Lock vacuum lines

At idle there was this hissing sound coming from this pipe. Once boost kicked in it went quiet (or the flow reversed).
Any ideas what it is?

You have your answer but here is a diagram that might help anyway.