Thought I'd throw this out there and see if my thinking is correct. I'm an Audi tech and Friday did an Audi paid 75K with brake fluid flush. When I was all done, the ABS and ESP lights came on, along with the park brake malfunction warning in the center display. I used the VAG (number unknown) brake fluid exchange machine same as I've done a hundred times before. It's been bugging me all weekend!

What I have is 01435 G201 brake pres sensor DTC. When cleared I have 0.7b static pressure. When the lights are on it shows (after the car moves a short distance) -39b. I made a TAC ticket but didn't have time to do much after that. Only anomoly is the brake pedal switch. MVB fields 1 and 2 do NOT show "operated" at the same time when depressing the pedal. Field 2 switches and then field 1 after further pedal depressing.

My question is this. Is it logical if the ABS module sees G201 pressure before it sees that the brake is applied, could that cause the 01435 and maybe -39b is when the module is in default mode???? I'm going to replace the brake switch of course and hopefully fields 1&2 switch simultaniously but that'll have to wait until tomorrow morning. I'd hate to have to replace the $1,600 (non-warranty) ABS ECU/HCU assy because the sensor is integrated.

Worse is, how could flushing the brake system cause this concern? Yes, I did try rebleeding the system again thinking an air bubble in the sensor but no luck. Suppose it could just be an unlucky coincidence also.......I hate when that happens, fortunatley it happens very rarely!

Any ideas, comments, thoughts on this concern? Thanks!!!!

 

Nothing? Oh well. I replace dthe brake lamp switch, now mvb 2, fields 1 and 2 both activate at exactly the same time, and with a lot less pedal travel. Unfortunatley,,,,,,,,,,,,,,,,,,01435 G201 fault comes back right away The static pressure will be OK at less than 1b, then it'll show -10b, -14b, -3b, -39.7b so looks like I'll be replacing the ABS ECU/HCU assy after all. Why me?????????!!!!!!!!!!!!!!!!

 

How did you flush the system? I would suggest trying to pressure bleed the system if you did not use this method to try to reset the valves in the ABS by pushing the fluid through the system the way it normally goes. If there is still trouble, see if you can use the VAG Com system to reset the valves. This won't make it any worse anyway.

 

I used the VAS-xxxxx pressure bleeder machine (Audi/VW required equipment), same as I've done a hundred times before. Talked to Audi Tech Assist and, unfortunatley, it seems the G201 just picked the worst possible time to fail. I've been a tech for 25 years and stuff like this happens every once in a while. From some other research I've done, sounds like G201 failure isn't an uncommon thing for the '05's.

Good news is, the customer is buying the part and my Service Manager said he'd cover the labor so I guess everyone will be happy(?). In the end, the most important thing is to make the customer happy no matter what you have to do (in every case, not just this one). Thanks.

 

Just to update an old post, last week I installed a used ABS unit from a local salvage yard, bled the sytem and all is well. Better still, it was only $400 vs $1,600 for new. Customer was very happy about that one!