ESP Fault

[Waffles_s4]

After switching my rear brake caliper line from the stock one to a steal one, I started getting an ESP light/beeps.

The rear parking brake still works fine without issues.

VCSD shows no errors, but when I select Module 3 (ABS), I do hear the beep and the ESP message. Still no errors.

The harness and abs sensor all look good.

Any ideas?

[mjessup]

Did you follow the proper procedure for bleeding your brakes? I would flush out all the old fluid with new while you are at it. https://www.audizine.com/forum/showt...ding-DIY-video

[Waffles_s4]

I dont believe its related to bleeding. I dont think having air in the system will trigger an ESP. The brakes are firm

[SwankPeRFection]

When are you getting the ESP beep and flash? Is it during braking or just out of the blue? If there’s no logged errors, then you might just be triggering the stability control during braking. Hopefully you did all the lines to the same ones, otherwise, having a wacky combo on any corner will throw off the brake proportioning enough to trigger ESP while braking even if not laying on the brakes.

[Waffles_s4]

When are you getting the ESP beep and flash? Is it during braking or just out of the blue? If there’s no logged errors, then you might just be triggering the stability control during braking. Hopefully you did all the lines to the same ones, otherwise, having a wacky combo on any corner will throw off the brake proportioning enough to trigger ESP while braking even if not laying on the brakes.

I literally turn ignition on (engine is off), and about 2-3 seconds later, the Fault appears in the dash with 3 beeps (red exclamation mark). No ABS faults or anything related to traction.

In fact, the parking brake works, the traction control works on all modes (Sport and off), cruise control works, and ABS itself works when I brake hard on wet/slippery surface. Car behaves and drives really well.

Did a full scan again, no errors logged.

[SwankPeRFection]

You sure you didn’t knock the ESP sensor wire or sensor loose or damaged it in any way? If you did lines, the back ones are really tight when removing the caliper and they need to be uncoupled so as not to damage them by tugging. I’d check that out again on that corner or all corners if you touched all the lines.

Also, if you swapped lines and you did the brake bleed procedure via VCDS, you need to drive the car around via the drive routine they describe for ESP readiness. If you didn’t do that, that’s why the ESP fault is triggering. It’ll actually show up as a code in the ESP/ABS module until that drive routine is completed. Basically drive around the parking lot and go in circles slowly left and right and then straight and it’ll go away and clear. It’s like the ESP version of setting readiness codes for O2 sensors.

[Waffles_s4]

You sure you didn’t knock the ESP sensor wire or sensor loose or damaged it in any way? If you did lines, the back ones are really tight when removing the caliper and they need to be uncoupled so as not to damage them by tugging. I’d check that out again on that corner or all corners if you touched all the lines.

Also, if you swapped lines and you did the brake bleed procedure via VCDS, you need to drive the car around via the drive routine they describe for ESP readiness. If you didn’t do that, that’s why the ESP fault is triggering. It’ll actually show up as a code in the ESP/ABS module until that drive routine is completed. Basically drive around the parking lot and go in circles slowly left and right and then straight and it’ll go away and clear. It’s like the ESP version of setting readiness codes for O2 sensors.

So far, I only did the rear passenger side, I have not touched any other sides (yet). I basically removed the rear caliper, changed the brake line, put it back, connected everything, and bled the caliper.

For the rear passenger side, I checked the ABS sensor and the parking brake sensors, they both work. How do I know? If I disconnect them, I get ABS/traction control related errors (actual errors logged). I am also able to see the wheel speed exactly the same on all 4 wheels. This tells me everything electrical should be fine in that corner. Parking brake works as well, no errors for that.

I did not do the brake bleed procedure via VCDS. Where can I find it? I dont see any codes under the ESP/ABS module right now...

[SwankPeRFection]

I know it’s not what you want to hear, but if you’re changing from stock lines to braided, you need to do all of them, not just one corner. Not sure why you chose to do just that, maybe I missed something. I’m reaching here a little bit, but the ABS/ESP module can see line pressure and wheel speed at all 4 corners and it’s possible it’s acting wonky due to that since there could now be a difference on just that one corner since it’s a different line. Again, I’m reaching a bit on this one and giving the car the “it’s too smart for its own good” benefit, but it is possible. Nobody would ever change just one line out like that and if it was due to a failed line, they replace it with the same type, so as not to run into this, IF this is what it could be.

For now, don’t mess with that bleed procedure in VCDS. If you’re not familiar with it, it can cause more issues than it’s worth. FYI, a quick check to see if you’ve got something wonky happening with any corner, especially the back corners, not braking at the same rate. Check temps on the rotors after a short drive. If one side is colder than the other, you’ve got caliper clamping issues on that corner which is either line, caliper or major air in the line. Ask me how I know and came up with that easy way to tell. Lol

[Waffles_s4]

I know it’s not what you want to hear, but if you’re changing from stock lines to braided, you need to do all of them, not just one corner. Not sure why you chose to do just that, maybe I missed something. I’m reaching here a little bit, but the ABS/ESP module can see line pressure and wheel speed at all 4 corners and it’s possible it’s acting wonky due to that since there could now be a difference on just that one corner since it’s a different line. Again, I’m reaching a bit on this one and giving the car the “it’s too smart for its own good” benefit, but it is possible. Nobody would ever change just one line out like that and if it was due to a failed line, they replace it with the same type, so as not to run into this, IF this is what it could be.

For now, don’t mess with that bleed procedure in VCDS. If you’re not familiar with it, it can cause more issues than it’s worth. FYI, a quick check to see if you’ve got something wonky happening with any corner, especially the back corners, not braking at the same rate. Check temps on the rotors after a short drive. If one side is colder than the other, you’ve got caliper clamping issues on that corner which is either line, caliper or major air in the line. Ask me how I know and came up with that easy way to tell. Lol

I am planning to change all the 3 other lines, but was trying to figure the ESC error first.

At this point, my next step would be to change the remaining 3 lines.

I forgot to mention that I also did the ABS pump bleeding procedure only for the rear passenger side (the one I changed the line for), and I did see a lot of air coming out after that. Is that the same as "Bleeding the brakes via VCDS"?

What should I do next?

[SwankPeRFection]

Yeah. That’s your issue. Whenever you run that ABS bleed procedure, it triggers a need for that readiness test I mentioned in the other post. Go drive around in a circle right and left and then straight. I’ll try and find the post I found on how to fix it. I ran into it as well when I my lines and did the ABS module bleed to flush the lines. I take it you are putting on a pressure bleeder on the master cylinder when you did the initial bleed and then the ABS bleed. FYI, unless you’re having issues with air anywhere in the lines or you’re wanting to flush the entire system if it hadn’t been done in a long time, you don’t need to do the ABS bleed via VCDS. And you’re also wasting your time doing that shit without swapping out all the lines. Swap out all the lines and then go and bleed all the corners per the Audi directions, which is FL, FR, RL, RR. Also, if the rears are not easily flowing when you crack the bleeder (like the fronts), just add more pressure on the master. Proportioning is a bit weak to the rears on these cars and I found I needed to be about 5PSI or so more to get better flow.

[SwankPeRFection]

Found it. http://wiki.ross-tech.com/wiki/index..._Function_Test

[Waffles_s4]

Thanks a lot!

Ok so the steps should be:
1. Change all the 3 remaining brake lines
2. Bleed them manually first
3. Bleed through the ABS pump
4. Drive around in circles and straight

Or should I do the circles before swapping the lines?

Some historical background: before all of this (before changing the rear brake line), I changed the disks and pads on all 4 corners. During that process, I pressed the brake pedal by mistake. So that introduced a lot of air in the system. So I did a full bleed through the motive pressure bleeder on all corners multiple times (I did not know the ABS pump procedure even existed). But I always had a mushy pedal. When I did the rear passenger brake line this weekend, and it was STILL mushy after bleeding, I found out the ABS procedure is a thing. As soon as I did it, lots of air suddenly start flowing, and the pedal started to get better just doing that one corner. And this is the actual state of things as of now.

[Waffles_s4]

one more thing, I did use the power bleeder at the same time as I used the ABS pump. I read it was OK to do so.

[SwankPeRFection]

Yes, you’re supposed to still have positive pressure on the system when you run through that procedure.

Not sure how you introduced air in the system by simply pressure the brakes after you changed pads/rotors…

Read the link I posted. That tells you exactly the steering degree and the drive procedure you have to follow closely to get it past that test state. FYI, if you’re not actively driving the car now, yeah, swap the rest of the lines and do all that. If for some reason you are actively driving the car now for some reason, which you shouldn’t, you need to at a minimum go through the ABS module readaptation test, but I wouldn’t be driving around one just one line swapped like that. Still kind of puzzled by you only changed one line and then decided to do all that bleeding, mostly because you’re changing lines types, not just a failed line of the same type/build. Anyway, get them all changed, bleed it all like I said up above FL,FR,RL and RR and test drive. You shouldn’t need to do the ABS bleed unless you still have issues with feel or old fluid still in the system you’re trying to really fully flush out. If you don’t plan on doing the ABS again, go ahead and just do the ABS readaptation drive procedure in that link before you do any other work so that’s all reset and you know you don’t have something else going on.

[Waffles_s4]

I did only one side because I wanted to have the car ready in case I need it for emergencies. So I did the rear/passenger side, and completed it. Then I actually had to drive the car before I get to do the other 3 sides, and thats when I got the ESC error.

So I should not worry about the ESC error for now, until I changed the other 3 lines + do the bleeding + ABS, and then take it for a drive, correct?

[SwankPeRFection]

No, fix the ESC error as it’s unsafe to drive if you’re presented with an emergency situation (handling or braking) until that’s cleared/readied.

[Waffles_s4]

Ok, I will try that, it should take less than 5 minutes. If that ESP System Function Test does not reset it, then am back to square 1.

[SwankPeRFection]

Follow the Ross tech write up on what to do. If it’s that, that’s the process. Read through it… it’s all there, including which informational codes are active when this is the case, etc.

[Waffles_s4]

I followed everything by the letter many times, didnot help. Also I don't have the error they mention in their site.

At this point, it's not related to the function test.

The fact that I have zero errors anywhere stored is not helping. Unless it's related to pressure for each brake line, but I need to replace all remaining lines (which I have to do anyway).

[Waffles_s4]

Any other ideas?

[SwankPeRFection]

So you’re saying that if you hook up VCDS and press Gateway Installation List to poll the vehicle everything is black on the list and no red (indicating modules have codes set off)?

Are you sure you did it like this?

https://www.youtube.com/watch?v=7AVPRj2BNuc

[SwankPeRFection]

You could always request the test to be triggered again via the drop-down in the ABS module and then actually do the test drive. It’s hard to believe the car is warning you about some kind of ESP fault and yet there’s no codes. Also, when you did the ABS bleed, did you actually bleed each corner as it prompted and pumped or just skip all except for the one back one you replaced the line on?

[Waffles_s4]

So you’re saying that if you hook up VCDS and press Gateway Installation List to poll the vehicle everything is black on the list and no red (indicating modules have codes set off)?

Are you sure you did it like this?

https://www.youtube.com/watch?v=7AVPRj2BNuc

I do see a red line for Module 3 (Brakes/ABS). When I then select it individually, the dash does beep three times (with the same ESC error), but I do not see ANY fault codes at all under Fault Codes. I also do not see the 01486 error mentioned in the video.

For the ABS, I did it only on the side which I changed the line, the rear passenger side. So far I have not changed the lines on any other corner, nor did the ABS bleed on them.

Thanks for your help btw

[Waffles_s4]

If the fault was accidently erased, is there a way to somehow pull it from somewhere? and why would it not re-appear? I did a full battery reset, still nothing logged.

[SwankPeRFection]

Something’s not right with the ABS module then. If it’s red, there’s something up with it. Might not be an error, might be you didn’t finish the bleed procedure since it prompts each corner. Not sure since I wasn’t there and didn’t see what you did or didn’t do. I suggest initiating the test procedure on it, which is on the drop-down option under ABS and Basic Settings I think. That should cause you to see the code for it and then have to do the procedure based on the video and writeup posted above. Try that. Bottom line though… you need to do the other 3 lines ASAP. I would never drive like you’re driving on it now, but that’s just me and I’ve done some sketchy shit. Find the time to do the lines, it’s a quick job. You don’t even need to pull the calipers off, just be mindful not to cross thread the new lines going into the caliper first and then the hard lines up top.

[SwankPeRFection]

FYI, hopefully the lines you bought came with a small black cap you’re supposed to put on the hard lines so that you don’t drip out fluid while you’re getting the new lines into the caliper first. If they didn’t, go find yourself a small rubber stopper to go over them and use that. It’s a cleaner process and you don’t run the risk of losing a ton of fluid and running the lines dry and making the bleed process more of a headache.

[Waffles_s4]

Something’s not right with the ABS module then. If it’s red, there’s something up with it. Might not be an error, might be you didn’t finish the bleed procedure since it prompts each corner. Not sure since I wasn’t there and didn’t see what you did or didn’t do. I suggest initiating the test procedure on it, which is on the drop-down option under ABS and Basic Settings I think. That should cause you to see the code for it and then have to do the procedure based on the video and writeup posted above. Try that. Bottom line though… you need to do the other 3 lines ASAP. I would never drive like you’re driving on it now, but that’s just me and I’ve done some sketchy shit. Find the time to do the lines, it’s a quick job. You don’t even need to pull the calipers off, just be mindful not to cross thread the new lines going into the caliper first and then the hard lines up top.

The error occurred before I even do anything with the ABS test procedure.

It just popped and no idea what to look for.

Yes I did indeed use the rubber plug, it helps a lot :)

[SwankPeRFection]

So, all you did was change the line, do a normal bleed and then that error was happening? Or did you start getting the ABS beep before the line change and after you were doing your rotors? Like, give me the change of events of how it happened since I take it all was fine before any work was done by you on the brakes.

[Waffles_s4]

Correct.

Here is the line of events:

1. Everything is fine, no errors or faults anywhere
2. Removed rear/passenger caliper to change the brake line
3. Changed brake line from stock rubber to SS
4. Put everything back
5. Bled the rear/passenger manually
6. Drove the car, and the ESC error started shortly after
7. Did the ABS pump procedure on the rear/passenger side, more air was bled
8. Error was still there after the ABS procedure, and this is the current state

[SwankPeRFection]

OK, then it could be the pressure difference thing I mentioned to you earlier. I’m actually interested now too if the damn thing is smart enough to see the variance due to that one line on the system and kicking an error line that, it’s someone impressive if that is it. Changing out all the lines and triggering that ABS system test via VCDS should fix everything. You could always try that now to see if it’ll clear it after adjusting itself that way. It either will or it won’t. You do need to do the rest of the lines ASAP though. Good luck.

[Waffles_s4]

I would be happily surprised if it detected the pressure difference and threw an error. Lets see if changing the other 3 line + ABS bleeding resolves it. Thanks for your help and I will keep this thread updated with progress

[Waffles_s4]

@SwankPeRFection: If I bleed the FL, FR, manually first and then with the ABS pump, and then do the RL, RR, do you think I would need to redo the fronts again, or they should be ok? Planning to jack up only 2 tires at a time...

[SwankPeRFection]

Just bleed normally and see what you’ve got after that. The ABS bleeding procedure don’t need to be done unless you have issues or suspect air in that part of the system. That procedure MUST be done fully and in the order it asks for. Don’t cut corners… you’ve already done that one and developed issues.

[Waffles_s4]

Ya I do want to do the ABS bleeding, I dont want to remove 4 wheels yet again. I am almost done swapping all the lines, just one corner left. I am also doing manual bleeding after each corner, then I will do the ABS once the manual has no air at all.

have you seen some kind of official ABS procedure from RossTech? Gonna try and find it

btw your inbox is full

[SwankPeRFection]

It’s full because I have stuff in there from 10 years ago that I haven’t had time to decide if it’s still worth holding on or not since returning to the forum.

If you stick the car on four jack stands it’ll be easier to go through the ABS bleed. When you start the process, VCDS prompts for each corner and when to open the screws and close them. You can’t really do it with just one wheel taken off at a time. That’s not how that’s supposed to work.

[Waffles_s4]

I thought ABS does the front 2 first (both at the same time), then the rear two (both at the same time).

Still trying to find the ABS procedure for a B8.5 from RossTech

[Waffles_s4]

@SwankPeRFection: Changed all lines, manually bled, still error. Then I did the ABS bleed, ESC error gone without even driving, just starting the car.

Pedal is finally starting to feel firm when engine is running. No bubbles when bleeding right now...

Not sure if I should just drive it for a week, or run the ABS bleeding one more time.

Thanks for all the help btw.

[SwankPeRFection]

If all errors are gone, just drive the car and enjoy it. If all feels good, it’s fine.

[Waffles_s4]

Quickly checked this morning, more air was coming out. Glad I did not put back the wheels yet. There must be a lot of air in the system, which was trapped in the ABS module.

[Waffles_s4]

Confirmed, the ESC error is still gone even after a good drive and hard braking.

The brake pedal is much better now, but I still think it can be better (or I forgot how it felt initially before all of this). That or there is still some air in the ABS module.