Ok, so first of all I just replaced my upper control arms and outer tie rod ends. Brakes and everything had no issues til I did this.. Once I was done put everything back together took it for a drive and noticed while coming to a stop the brakes would grab. So I checked the fluid, fuses for abs etc. The abs light is not on. I took the wheels off and sprayed them with brake cleaner thinking maybe some PB blaster got on the rotors or something or thought it could have something to do with all the hammering and beating the upper control arm pinch bolt took! That was a PITA by the way! ANyway, so I started to monitor when the brakes would grab, when slowing down from 15mph-10mph the brakes grab then let go. It ONLY does this between those two speeds! I can ride the brakes from 60-0mph but when I get to 15-10 it grabs and you can feel the brake pedal push back toward you. I took the wheels off cleaned out the abs sensor but still did not fix this issue> SO I am thinking ABS sensor or speed sensor? Any other suggestions? Thanks in advance!!

 

Sounds like you figured it out. I have the same problem but between 1mph-5mph. My mechanic said it sounded like the wheel speed sensor. If you have the tools or are near someone who does, you can check wheel speeds to determine which wheel is the problem.

http://www.ecstuning.com/Audi-B5_A4-.../Speed_Sensor/

You could contact ECS over the phone and ask them which part you need for your car's year.

 

Awesome, Thanks for the info! I just find that very strange that this problem happened as soon as I replaced those parts lol But I guess thats what I get for fixing a ton of other problems! I just recently did coolant temp sensor and the coolant flange, then all the battery, then all the control arms and stuff.. I dont even want to think of what could happen next! Im willing to bet it is one of my front two sensors since that is where I was working at on the car. Ill just buy both front ones. I just do not know if mine has the brake wear sensor or not. Ill have to figure that out. Thanks again!

 

OK, so today my ABS light came on and the problem stopped! Then I shut the car off and drove again and light was OFF and problem came back! Grrrr.. So, is it the sensors just playing games with me now? And that really is the issue? I am most likely going to get both sensors and just replace both. But is there a way to test the ABS light when it is on to see what the issue is?

 

Also, if anybody has the part numbers for the front ABS/Speed sensors I would appreciate it. Thanks!

 

http://www.ecstuning.com/Audi-B5_A4-...T/Braking/ABS/

 

Thanks for that, but how do I know which one is for my front? I do not know if it has brake sensors or not. How can I tell?

 

Call or use the chat feature on ECS Tuning and they can help you out for specifics (as long as you get someone competent). Calling a service dept at a dealership might work too.

 

Alright so here is an update.. I was able to remove and replace one of the ABS sensors (passenger side). I found that if u tap on the old sensor with a hammer then use vice grips right on the edge of the sensor and twist and turn the sensor while pulling it out it comes out really easy! Just thought I would throw that out there if anyone wanted to know how to take it out. But back to my problem, I replaced that sensor took the car for a drive and the problem still exist! If I buy and replace the other one (driver side) and that does not fix the issue what is the next thing to look into??? I am at a loss right now and do not know what to do after that. Thanks for any advice or info I appreciate it!

 

OK well just an update I replaced the other ABS sensor on the front so both front ABS sensors and the issue is FINALLY fixed! Hopefully this thread will help others in the future! Thanks to the VERY FEW people who had any insight on the issue but I think I will be looking for another audi forum where there are more responses to issues. Thanks!