Abs fault on vw passat

Question edited for 'brake' and to add maker..

Well documented issue. Check the brake fluid, then the pads and then the ABS..

https://www.passatworld.com/threads/brake-fault-stop-service-manual.223013/


https://www.google.com/search?q=2004+VW+Passat+brake+fault+light

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If it makes a clunk-clunk-clunk sound while turning, it's your front CV joint that's bad. Check to see if the front CV rubber boot is ripped/torn, on either side of the car. The CV boots are located inside/behind the wheels, where the drive axle hooks up to the wheel. If damaged, you will probably have to replace the entire CV axle.

I had exactly the same problem with my 2003 tdi, 'scary stuff for sure' Lots of so called experts knew what the problem was, (brake pressure switch).. (ABS sensor at the wheels) .. (ABS control module)..Trial and error and lots of expence for sure, no thanks, keep away from from the backstreet cowboys and go to the people who specialise in VW repairs every day and who know what they are talking about. My main VW dealer sorted it, they found it was a problem with the YAW Sensor located under the rear seat, they cleaned it and checked it and reset it etc, they didn't even charge me ( I did have a new clutch and 2 outer CV joints fitted at the time) and now it seems ok, hasn't happened since, actually this seemed to happen more often when I had 2 or 3 people sitting in the back seat and the ESP light came on at the same time, hope you sort it soon

its possible abs sensor is in hub assembly abs sensor may not have been hooked up correctly or wire/ connector may have been damaged when cv joint was replaced bring back and advise shop of issue

Not likely> there are 2 wires that are connected to the break pads that could have came unhooked

This is caused by excessive ABS sensor air gap. You might need to adjust the air gap on the speed sensor to the new cv shaft.

The ABS control unit is failing, this is a very common issue with the 98 and 99 model Passats. You will need to have the ABS control unit replaced. You can now purchase the ABS control unit by itself but it is still pricey. Depending on which pump you have will determine which control unit you need to get. The run around $600 - $750.00 plus labor to install. The control unit needs to be installed by some one with a factory type scanner, as the new unit will need to be coded for that vehicle.

No.  Go to another shop,and don't return to this place if ALL they told you was the boot was broken. Sounds like you know about as much as the shop you went to ... you wouldn't want to pay you to work on your car, right?
If they had said a tie rod end was bad, you could go back, but based on your description of what they told you, I  wouldn't let them fix a flat.
You have a 2001 Passat,and at that age ALL front wheel cars will need new CV boots.  The front outer CV boots are probably both broken and need to be replaced, but this has nothing to do with the pulling.   If you ignore the boots, you will be buying 2 rebuilt axles or 2 new CVs in the next year or two.
You need to find a reliable shop in your area that work on VWs or Audis (essentially the same thing).  Many shops will not touch VWs.  Check for a VW club in the area and ask around. If you are going to keep this car, any time consuming research you do to find an honest VW mechanic will pay off.

You need to go to an QUALIFIED alignment shop and ask for a 4 wheel alignment. This shop should do only alignment, NOT be a tire store.   If they are competent, they will notice any suspension problems and tell you what to get fixed before they can align it.  Make sure that they think that alignment will resolve your problem, and get them to agree if it doesn't, they will align it for free in the next month or so, when you get the front suspension fixed.   
One of two things are causing the pulling
1. First when you lent your car to your college buddy last year,  he hit a pothole or a curb or something so hard as to knock the suspension out of alignment.  Or possibly the alignment is out fo other reasons.
Or 
2.Some suspension part was worn out,  check with the VW dealer for recall notices on either upper or lower control arms, (98 Passat had recall on one of these).  

was the fault code p04020 or has it failed the mot.need more details then will be able to help

Dear All

After taking the car back to our most excellent garage they quickly diagnosed the fault with the ABS. It was to do with the gap between the sensor and the wheel - it has to be a very precise distance and was disturbed by the changing of the CV boot (seems to be a common problem).

Half hour later and it is as good as new - this was after lots of electronic testing etc. - the clue was that it didn't give any registered fault on the diagnostic computer.

Hope this helps you Saxoste

Jon A