'99 A6 ABS light on. Controller not recognised.


Registered User
Hi guys,

I have had the ABS light on the car for a while.

When changing my alloys I found the front brake sensor wire had snapped, so I replaced the brake pads. I then tried to clear the fault.

But vag.com or Bosch tool.

Could not connect to the controller. No communication

IS there any other way to clear this fault.


Ross-Tech, LLC
If neither tool can connect to the controller, check the fuse to the ABS controller, check the wiring to the controller, and then replace the controller. It would be helpful if you posted a full auto scan of the car so we would have full information. For instance, did the tools connect to any modules in the car? What version of VAG-COM were you running and what interface were you using?

There are many possibilities to be considered. More information usually leads to better assistance.


Registered User
I had an ABS problem with the warning light showing and my local specialist's diagnosis software couldn't communicate with the ABS module. In virtually every case, he told me, this indicates a knackered ECU and sure enough that was the problem. BBA-Reman fixed my module for me for about £100.

The OP may not care enough to reply to helpful posts in his thread, but perhaps other people searching on related matters (like me!) may find this useful in the future...


Registered User
Fair enough