2003 Audi TT Engine troubles - Loss of power

[dancov]

Having some trouble with a 2003 Audi TT 180 seem's to be losing power during normal driving no warning lights from the engine management. Have been told by the local non Audi garage that this problem could be a result of a faulty brake light switch can any confirm whether this is true or shed further light on the situation?

Previous experience suggests a faulty coilpack but such symptoms usually bring about an engine warning light but this does not happen on this occasion.

Any help / advice appreciated

[Robatr0n]

Is it a sudden loss of power? Almost like a fairly agressive cut out and then the power returns, or does it feel like the aircon is on fully kind of power loss?

[sublimatica]

The throttle-by-wire systems do seem to cut power if the brake pedal is pressed, so I guess a faulty switch could cause a loss of power. It'd be pretty dramatic though. If I hold the brake in my Tiptronic A6 and press the throttle the revs build a bit, but drop back down to idle very quickly.

[Gren]

I know for a fact that in my TT pressing the brake does not cut out the throttle.

As asked above, is it like an on/off switch or is it like the turbo has gone 'off line'? Could be issues with collapsed/leaking hose or MAF failure.

Had the coil pack problem and this doesn't sound like it. Effectively you lose a cylinder and that's pretty easy to recognise - juddering, noise and smell!

Get it to a dealer or someone with VAG-COM setup - diagnostic check should highlight the problem.

Edited by Gren on Tuesday 19th December 08:36

[dancov]

its a fairly harsh drop in powerthe power drops then returns slowly but with no noticable engine effects e.g. missfires, juddering etc after having had an engine diagnostic today the suggestion is its a faulty brake light switch but I fail to see how this would cause such a problem.

Just a thanks as well for all the help and advice so far

Edited by dancov on Tuesday 19th December 20:12

Edited by dancov on Tuesday 19th December 20:15

[sportsandclassic]

Normally with a failed brake light switch you would get a ESP error as well as that system uses the brake light switch too .....

Just get it on a machine with someone that can use it properley and have a look at all the actual values....ie coolant temp and air temp..see if you can borrow an air mass sensor to try.....ect ect.

mike

sportsandclassic

[wicked1]

It sounds more like airmass meter, with the correct diagnostic equipment you will see the airmass meter reading as being low, an oscilloscope would show the meter reading as well. These are extremely common to muck about and generally aren't designed to last above 50k. Proof in this fact is simply ring your local dealer and ask if they have one in stock, they don't usually stock parts that don't sell.

Mat

[Imadreamer]

Also could be the turbo bypass valve (dump valve) as the standard items are fairly crappy. Also check that you don't have a loose hose somewhere between the turbo and intercooler.