[A4] ABS problem

Richard van der Hoff quattro at rvanderhoff.org.uk
Mon Jun 9 10:15:42 PDT 2008

Richard Andrews wrote:
> Usually module cause the abs lights to come on while driving.
> I would clean the sensors before doing anything to the module.

Agreed. I had very similar symptoms, and it went away by having one of 
the ABS sensors replaced.

Apparently the wiring goes brittle, which leads to intermittent 
connections, and the sensors working fine until you start to brake, or 
something. Anyway the vag-com/prodiag are a bit useless, because, as 
you've observed, they disconnect from the ABS unit above about 20mph.

But the sensors aren't cheap, and replacing all four to find out which 
is dodgy doesn't sound fun. If cleaning the sensors doesn't help, you 
might try experimenting with an oscilloscope and turning the wheels I guess.

I don't see much evidence to point to a flakey ABS module, in any case.

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