HELP brake system error

[SpanishS2Avant]

I need help to diagnose a brake system error that i have had since buying my S2 Avant. Everything else on the S2 is great now just had a full service and had some hoses replaced and belts done also, basically a through check up so pads/discs must be good and brake fluid was already nearly full.

The main stealers near me reckoned it was a wheel speed sensor error and thats what it shows when plugged into VAG-COM, but later on a local garage was doing the service they came to the same conclusion but after fitting 2 new wheel speed sensors on different wheels the error did not go away, so they sent the sensors back.

My S2 is now almost perfect in my eyes apart from this very annoying flashing and beeping error i would really appreiciate any ideas what could be causing this.

EDIT: Also maybe unrelated but the differential wont engage as far as i can tell (when pressing button no light comes on).

When applying the brakes the first time after starting they are noisey like a clicking/sliding and not too safe as there is alot of travel before coming to a standstill but as soon as the brake system error appears on the computer they are strong and responsive.

I being no expert would guess its as if the ABS is trying to engage but then gives up and switches off which then gives normal braking but without ABS

[CP951]

Perhaps your power steering hoses are leaking and the reservoir is low in hydraulic fluid. My understanding is that low brake fluid / hydraulic fluid level will give the same fault signal.

[CP951]

Ooops. Sorry I didnt see your ABS fault light is also on? Maybe there're 2 faults then? Low hydraulic fluild + faulty ABS pump?

[CP951]

Or is there right lower corner rectangular signal light your handbrake light? I couldn't tell.

[AAH!]

Assuming you are talking about the flashing (!) symbol I had the same problem for a year or so and it finally went away when I changed the brake bomb.

[S2 Ant]

Bit warm there as well by the looks of your temp gauge.... +40 degree's! Feeling hot hot hot hot!

Sounds like possibly bomb, also check levels.

@CP591 - Thats the handbrake light, ABS light is yellow and is central on that cluster of 3x3

[SpanishS2Avant]

The Bomb sounds bad i will get it checked.

hydraulic fluid is full also brake fluid even before service but may have been a slight leek of the Hydraulic fluid as i had to top it up before the full service. I used green mineral g00200 VW/Audi stuff.

Could a small leak be detected by the computer causing the brake system error even if levels are topped up?. This leak should have been sorted during service!!

ok just read 100+ posts on the Pressure reservoir or accumulator or aka Bomb, gonna try the peddal pumping test.

OMG i wish i could drive over for the Garage meet, theres so many reasons and solutions to this problem its making my head spin...

@Ant - The light at the bottom is the airbag light on my S2 but that is fixed now (its an old picture hence the +40 degrees middle of last summer )

[rotoryboy]

Just check all connections. I've had this trouble for a while now and have found that one of the connections was loose, so was loosing pressure and fluid slightly

[SpanishS2Avant]

Ok heres a question for ya! I just got my S2 back from a full service which they werent able to clear the brake system error or the airbag light gonna have to take it to stealers and bite the bullet i think. They did get the abs working again after replacing they faulty wheel speed sensor.

But now to add insult to injury i have white smoke coming out of the exhaust and its quite embarassing when sitting at traffic lights/town driving it starts as whisp then bellows out blinding everyone behind me could it be they over filled it with oil??

What do you think i should do about the smoke? Car is running well and feels stronger through the gears now has new sparks/full oil change.

[Jon441cc]

What grade oil did they put in ?

[keithsw0]

sounds like brake acumilator i had same prob replaced it now fine part is £200