Abs light on constantly but no codes coming up

[A31998]

I've got a Audi A3 1998, the abs light is on all the time yet when I plug in my reader no codes to do with the brakes come up, I have a speed sensor one but that is it? Also airbag light is on but nothing comes up for that either, anyone got any ideas? It's due a mot too but would it fail because of abs light or airbag light?

 

[desertstorm]

It would fail if either light was on. What are you using to read the fault codes ?
A cheap VA-COM lead can be had for £6-£7 to use with VCDS-Lite.

 

[<tuffty/>]

Whats the actual 'speed sensor' code? I assume you are using a generic reader too...

As Karl said really, get VCDS Lite and read them again... generic readers don't give enough info on VAG cars

<tuffty/>