da40flyer

I have a 2011 Q5. I went to bleed the ABS today following the Ross-Tech instructions, but I get an error saying that Group 001 is not available. Has anyone else seen this? Any suggestions?

Thanks.

spijun

What you really want to do with the ABS system ?
Be careful and attentive

da40flyer

I have 50K miles on it, changed pads and did a complete fluid flush... so want to bleed the ABS...

spijun

Who told you to do so through the ABS system ???

Procedure replacement brake oil in PDF

Good luck

da40flyer

I am not sure I understand your question... I did a complete brake fluid flush and want to also replace the fluid in the ABS system. Opening the abs valve with the vag com allows it to be flushed (as I understand it)...

spijun

Who told to work with vag-com on ABS ?????

Read the PDF manual for replacement brake oil, no mention any electronic intervention from a computer to the ABS system
Attached is a PDF from an electronic catalog of services VW groups that used Audi services in the world

Good luck

MP4.2+6.0

BTW, for others maybe tone down some of the skepticism/push backs a bit. I think there may be a bit of misunderstanding here that's not getting to an answer or effective help.

For OP (and sorry if this is already obvious), the brake fluid basically goes from the reservoir through the master cylinder, through the ABS and then to the wheel brake calipers. If you bled the system by keeping the reservoir filled the whole time, there should be no air in the ABS. On the other hand, if you let it run dry at any point, that's not good and then it can be pretty darn hard to get it out again.

Thus, if you know you didn't introduce air into it, you're done. Or, if you aren't satisfied with pedal feel, bleed again--as usual from furthest (far back wheel) to nearest (driver's front wheel).

If you have air in ABS (or think you do), what you are referring to is cycling the ABS. That used to be pretty routine years ago on vehicles like my 2000 A6 with ABS that was pre-ESP, but got more complicated from what I understand on my 2006 A8 with ESP (and thus, I'm extra careful now never to let reservoir run low). You would need to either look at shop documentation or maybe get it to a dealer if you are stuck in this scenario.

And yes, of course it does still happen in car maintenance--by definition it's inevitable if either the master cylinder or the ABS hydraulic unit is replaced or removed. You can look through the Ross-Tech instructions further, or do some on line searches. Look at recent A/S 4's and 5 posts too since you are dealing with essentially the same system. And yes, if air is in there it will continue to have a softer pedal feel

You can also try a power flush unit--basically like what is in spijun's attachment that dealers, many shops and some DIY'ers use. With reservoir full, applying pressure allows the fluid to be pushed through as you open the bleeders.

da40flyer

Thanks Mp4...

I used a power bleeder through the MC, so I am almost certain no air was introduced. The reason I thought I may need to cycle the ABS is that with the car off, the pedal pumps up fine and holds position with pedal pressure. If I then start the car, the pedal slowly goes all the way to the floor. I thought that maybe it was the MC leaking past its seal, but I would assume it would then also go to the floor with the car not running. I have checked for leaks and even re-bled the system. Not sure what to try next...

MP4.2+6.0

I have had air in my 2000 A6 where you can cycle the ABS, and pedal never goes/sinks to floor. It is just soft/mushy. Instead, that sinking sounds like master cylinder as you are suspecting. I had that happen on one old prior Audi, among many I've owned, and many brake flushes along the way. I bleed the old fashioned way, with a second assistant to pump. In one case with pedal traveling to floor, it did apparently tear a seal in the master cylinder. I replaced it and the sinking problem was solved. If it helps, the other technique I have heard occasionally is rapid jabs to the pedal; basically something instead of cycling ABS where you are trying to force air bubbles through and not give them a chance to rise back upward and stay caught in the ABS internals like they might w/ gentle pedal strokes.

Search the forum here, and maybe also the later A/S4 and A/S5 boards if more ideas needed. The Q5 is still new enough there aren't a whole lot of DIY'ers. Or, do it via Google w/ your choice of search words and point it at Audiworld by including: site:audiworld.com in your search terms. Can try quattroworld too (which uses the Google search engine anyway), but there are typically more posts on AW.

spijun

If you think there is skepticism because I asked who told him that he is using vag-com for oil change and attach a PDF procedure changing the oil in the brakes and my warning to be careful with ABS, OK I apologize


PS: ABS system You can "destroy" or disable to work properly if you do not know what you are doing with computers, which can be very dangerous and costly for repair

On YouTube you can find a lot of videos how replace brake oil

ABS Brake Pump Bleeding

Ross-Tech is not responsible for any damage or problems that may result from following these instructions. They are to be used at your own risk. These instructions apply to many older VW/Audi models but may not work with many newer ones. As always, you should refer to a Factory Repair Manual for your vehicle! Also check the Ross-Tech Wiki to see if there are vehicle-specific instructions that you should use instead.
http://www.ross-tech.com/vag-com/cars/absbleeding.html