I have a 1999 A6 Quattro with ABS. Recently the Brake light and the ABS light started coming on at the same time, accompanied by a pinging sound (warning beep). The lights don't always come on, and you don't have to hit the brakes to make them come on. Just drive the car and eventually they come on. I've checked the fluid level in the brake reservoir under the hood up by the top cowl area, and it's right at the top mark. The brakes seem to work fine. I took it to my local service guy, but he doesn't have the necessary equipment to scan for the fault. I'd like to avoid the dealer for obvious financial reasons. The car is in great shape, it has about 80K miles on it. Anyone have any ideas what could be causing this? Thanks!
Doug

 

I would take the wheels off and check your brake pads. Jut because they feel fine don't mean they actually are. Your ABS sensor could possibly be bad but I doubt it, I would just change the brake pads and brake lines to see if anything got damaged.

 

It could be the ABS wheel speed sensors, and you should check that out.If you can find someone with a VagCom, they can run a scan and see what the controller is telling you. Another possibility is that your ABS control module is on the way out. Check out www.ModuleMaster.com. for more info.

 

Would worn brake pads cause the ABS and Brake lights to both come on? How do I check out the wheel sensors? Is there an easy way to do it without expensive equipment?

 

Worn pads would cause the brake fluid level to drop, which can trigger the BRAKE light. Since you stated that the fluid level is good, that doesn't seem to be the case. If you have a bad control module, it will throw a code that indicates no communication with the instrument cluster, or something like that. Lots of people have the VagCom tool and are willing to help out - check this link and see if there is someone in your area:

http://www.steve-hall.com/cgi-bin/VAG-Locator.pl


Here's another link with loads of good info:

http://sonolithics.com/files/a6_links.html

 

My '99 Avant was doing the same thing. Eventually, the lights stayed on permanently. I decided to test the ABS on wet pavement with no other cars around and discovered that the ABS was inoperative. I'd do that test first.
I found a place that reprograms ABS units on the Internet. www.bba-reman.com. I removed the module (they provide instructions) and sent it in. I was still able to drive the car (just no ABS) while it was out. It cost about $140. They can do an exchange for about $400. Prices depend on what options your A6 has (Nav, ESP, ASR). I got it back in 3 days, installed it and tested it . All OK. The dealer wanted $800.

Well worth it. I liked the idea of keeping my module instead of an exchange - you never know what you're gettingwith someone else'sused unit.

 

These guys are good. I'm going to be sending my unit in.
http://www.modulemaster.com./audiabsbsrepair.html

 

I had both lights on a while ago. Took it into the dealer (still under warranty) and it turned out to be a switch under the brake pedal that was sticking.