ABS & ESP lights, but no fault codes.

[Toblahoe]

Hi all,

The girlfriends A3 is having abs trouble again, the abs and esp light are staying on and not going away from engine start.

I plugged in an OBD scanner and it only picked up a couple of Egr and emissions codes.

However, she's just had massive repairs carried out like reconditioning of the abs pump (see attached) I'm going plug in my VCDS tomorrow to see if it brings anything else up, do any of you have any ideas?

Thanks

 

[Retroman]

I'm not totally sure that an OBD II reader would pick up ABS type faults - the VCDS system may give you a more comprehensive idea of the problem. The obvious line of thought is that the fault is linked to the work recently done. However, if you assume the work done is not the problem, then one possibility to check is the battery. A failing battery can sometimes cause limited voltage to things like alarm systems, central locking and ABS as the car's ECU struggles to ration voltage to the main starting and running functions.

 

[leshkin]

Not all faults are part of the standard OBDII protocol, with many very useful ones falling into the VAG proprietary protocol, which VCDS or other VAG-specific tools would pick up.

Not sure what year your GF car is, but earlier A3 models suffered from a bad ABS pump design where a brake pressure sensor in the pump itself would fail and most pump reconditioning places permanently fix the problem with a slight modification during the rebuild. There are some codes that help to identify if this is the case here. Can the garage not provide the exact codes they saw?

 

[desertstorm]

Most generic OBD scanners will only pick up faults with the ECU as this is the only module they will talk too. To talk to all the modules in the car requires the use of a more sophisticated scan tool. But if you have VCDS that's not an issue this will show you the fault.
How long ago did you have that work done as it's a lot of work thats been done. I would read the fault codes and if it's anything related to what they have done I would be taking it back to the garage where the work was done.

 

[Toblahoe]

Work was done about 2-3 weeks ago and did involve a full reconditioning of the abs pump. A failing battery could be possible as its been struggling to start the car sometimes in this cold weather. And FYI it's a 04 plate with 150k on clock.

 

[desertstorm]

I would be taking it back to where the work was done after I had checked the fault codes.

 

[Toblahoe]

Hi, my VCDS won't scan the abs module , it's connecting and will connect and scan the engine and will pick up fault codes, but when I try to scan ABS, it just says "no response from controller"

 

[Toblahoe]

Okay I cleared her egr codes via VCDS and started the engine after unplugging and boom, engine management light gone, but so has the esp light, so only the ABS light on now?

Also apparently I don't have a genuine Ross tech cable so I can't scan everything...

 

[Toblahoe]

Okay, the fault codes have cleared themselves? They're not on today at all, but I didn't clear them, could this be because of the battery?

 

[Retroman]

Quite common for low voltage output from an old battery to cause ABS/traction control systems to shut down. Certainly happens to some BMWs and Mercs. These systems are considered “non-critical” and must require significant battery power. Why not get the battery checked to eliminate it from the possibilities

 

[Toblahoe]

Thanks, will get it checked soon, still no lights on all day today. Weird car haha