Coil pack replacement (edited) Now a code query!!!!

[sar]

i have had the dodgy brake switch which resulted in the brake lights being constantly on but no misfire/hesitation though?.

[Audi Pardner]

It's really weird. It can't be co-incidental, it's run fine today over 100 mile, whereas before it was only a few miles before the misfire occurred again.

[PetrolDave]

So it appears that when the switch fails the car logs the error but for some reason it results in a misfire/hesitancy.

Some brake switch failures make the engine ECU think that you're applying the brakes, which makes it "adjust" the injection/ignition timings and create a feeling of hesitancy or misfire.

[Audi Pardner]

That would make sense PD, and is consistent with the symptoms. Thanks

[ewand]

Hi everyone - reawakening an old thread, also to chime in on the brake issue.

I had an issue today where the car went into some sort of limp - the power just died, and foot flat to the floor, the revs were falling. Lifting off the accelerator completely and then reapplying throttle, it had a bit of think then started gradually adding power again. The EPC light came on, but only after about 15 minutes of this behaviour.

Had a look on VCDS when I got home and I too saw the 001393 - Brake Switch (F): Implausible Signal / P0571 - 008 - Implausible Signal fault. On checking, the brake lights are on all the time when the ignition is on, even (bizarrely) when the brake light fuse is pulled (?).

Am I right in thinking the brake light switch could be causing this? And if so, is this (http://www.audizine.com/forum/showthrea ... ght-Switch) sufficient instruction to replace it?

thanks in advance,
Ewan

[Audi Pardner]

Yes, that's what I did to replace mine. The click is important though otherwise it doesn't work. Strange that the chap's car didn't go into limp mode though.

[Rick_RS4]

just changed mine tonight, looked like a different part, but most probably a newer model.

i didnt have to click it to pull the pin out it was already out and works when you press the brake so must be ok

hopefully it fixes my fault, but my code said MAF and not brake light switch

[ewand]

Did mine this afternoon but the problem's still there - the switch is working OK (sat in the car with VCDS for about an hour) but the "BRAKE TEST SWITCH" is showing as active all the time... don't suppose anyone's got a clue what could be causing that?

I think I've got bigger issues, TBH - Cruise Control is inoperable now and I'm getting DTCs saying things like:

00466 - Control Module for Steering Column Electronics (J527)
49-10 - No Communications - Intermittent

9412 - No Communication with Cruise Control Module
U0104 - 008 - Implausible Signal - Intermittent

049446 - No Communications with Steering Angle Sender (G85)
U0126 - 008 - Implausible Signal - Intermittent

Bugger.

[Rick_RS4]

when the switch comes it is in fully closed position, you have to open it before you instal it. although i didnt on mine

where is the brake test in VCDS

[ewand]

The part I bought (http://www.eurocarparts.com/ecp/c/Audi_ ... d9a&000415) doesn't need to be locked out first.

Brake test in VCDS is in the ABS module, under measurement blocks.

[mongo]

Just so people are aware, the warranty campaign/service campaign 28E9 for the Coils is still open.

My March 2006 car had the 715A stick coils. These were replaced by Lomond Audi at Edinburgh for me under this warranty campaign, who also checked and confirmed it was still able to be carried out under warranty beforehand.