TheHersh

I have read a good bit on this problem and can't seem to find anyone with the exact same set of symptoms, hope someone with more mileage under their belt can help me.

Have a 2002 s4 with 6mt. When I start the car I have no indicator lights or warning lights. Once I get to approximately 10mph the abs and ESP light both come in together.

I had my mechanic run a scan and he came up with a bad o2 sensor which I replaced and got ride of my CEL. Also code for intermittent brake light switch (f) which I replaced and didn't seem to help. The other error code was for abs unit signal, but I found that was just a plug I pulled out when doing o2 sensor and reconnected.

Anyone have any idea what may be causing this? Speed sensor maybe? Going to have another session with the vag-com next week but wanted to get some ideas.

Thanks in advance.

jamesdmanley

i was looking at a car with a similar problem. i think i found a thread about this same problem that indicated it was a problem with the abs pump

TheHersh

Do you have the link for that other posting? Does anyone know if there is a way to check to see if the abs unit is actually bad before I go yanking it and sending it off?

The Codes that were pulled....

p1131 - Bad O2 Sensor (which i replaced)

p1649 - Missing Message from ABS Controller (unplugged connector, which i must have pulled when replacing the 02 sensor

p0571 Brake Switch (f) Implausible Signal - Which I replaced with OEM 2 pin

jamesdmanley

i found the thead here, but i dont recall exactly what i searched for to find it.

TheHersh

I'm not throughly convinced it's an abs unit though because it doesn't give the warnings until after I get moving. I will update when I run it on the vag-com again and update.

bkeen

I just had the same thing happen to me under acceleration, it lasted maybe 2-3 seconds then they both went off...did you or anyone else determine a cause?

bkeen

So for those who care or run into the same problem with the ABS and Traction Control light coming on simultaneously I replaced my O2's and the problem didn't go away...I then ran the codes again and found out there was a boost problem. After tracking down the leak I replaced the torn throttle body boot with a Samco silicone piece...haven't had the problem since.

MonroeS4

I can't figure how a boost problem causes ABS/ESP errors. I would suspect a faulty ABS sensor or displaced Tone ring. The ABS ECU failures usually fail solid, without need for movement as it's an Open Ground circuit within the ECU that fails. I would not be surprised when it comes back. Good luck.

snyderjm

Have the same problem.. just removed the TBB and indeed... it is ripped. I'll let you guys know if replacing it fixes the problem.. would be weird though.