Brake servo restricted

[paul-k]

Just had the same message appear on my 66 plate A4 2.0TDI.  

Called local Audi garage, can't fit me in until Monday.  

Read the forum and then called their parts team who told me that there is no stock of that sensor in the UK and there is a 6 to 10 day lead time on getting the part.  Waiting for a call back as I don't want to run into the ABS issue by carrying on driving it (I do about 30 miles a day round trip to work and back).  

Seems like this is a major part failure across the range, so hard to believe they aren't doing a recall!

[Norm Rees]

When I had mine done week or so ago, the garage said the sensors were on back order but couldn’t say how long they would take. 
I paid extra to have the sensor and the pipe, surprisingly it came following day. Sensor fitted and back to normal. Could you go down a similar route?

[AdamBoxall]

Mine's currently in the shop now but they're having issues reproducing the warning / symptoms. Apparently it's running fine and no fault codes, either current or historic.

I saw the message pop up on the screen behind the steering wheel when I first felt the problem though, which is what led me to this thread. I'm guessing the warning isn't registering like a normal engine fault?

They're going to try again tomorrow, but if they can't reproduce it and I end up picking it up, assuming it's all running fine, am I in danger of destroying the ABS unit? Or is that only a risk when the warning's consistently popping up?

Cheers

[JM Botteri]

Hi Adam,

I had a similar situation: the message appeared in January for maybe about a week, then disappeared for a couple of weeks (after I topped up the air in the front tyres but maybe it’s unrelated). When it reappeared it went into brake fault pretty quickly and as you can read above it didn’t end well for my ABS.

I would really insist with Audi because it can end up being very expensive.

Best

[paul-k]

On 5/4/2021 at 4:52 PM, paul-k said:

Just had the same message appear on my 66 plate A4 2.0TDI.  

Called local Audi garage, can't fit me in until Monday.  

Read the forum and then called their parts team who told me that there is no stock of that sensor in the UK and there is a 6 to 10 day lead time on getting the part.  Waiting for a call back as I don't want to run into the ABS issue by carrying on driving it (I do about 30 miles a day round trip to work and back).  

Seems like this is a major part failure across the range, so hard to believe they aren't doing a recall!

Despite being quoted 6 to 10 days, the sensor arrived yesterday and I fitted it this morning.  Message now cleared!  Thanks again to the guy who recommended doing it myself, saved me well over 100 quid!

[liquid]

My Wifes Audi A4 2017 Diesel Estate 2.0 TDI  Stop/Start & brake servo restricted error messages just ordered   https://www.ebay.co.uk/itm/353453734594?hash=item524b7bfac2:g:oGYAAOSwe-NgYtJU the part, will let you know how I get on, but 1 garage I rang was telling me that some ABS part might have to be sent away for testing around 10 days, this is just over the phone with out even diagnosing ! 

  

 

[Steve Q]

4 hours ago, liquid said:

My Wifes Audi A4 2017 Diesel Estate 2.0 TDI  Stop/Start & brake servo restricted error messages just ordered   https://www.ebay.co.uk/itm/353453734594?hash=item524b7bfac2:g:oGYAAOSwe-NgYtJU the part, will let you know how I get on, but 1 garage I rang was telling me that some ABS part might have to be sent away for testing around 10 days, this is just over the phone with out even diagnosing ! 

  

 

Keep us posted on how you get on 

[AdamBoxall]

On 5/5/2021 at 4:59 PM, JM Botteri said:

Hi Adam,

I had a similar situation: the message appeared in January for maybe about a week, then disappeared for a couple of weeks (after I topped up the air in the front tyres but maybe it’s unrelated). When it reappeared it went into brake fault pretty quickly and as you can read above it didn’t end well for my ABS.

I would really insist with Audi because it can end up being very expensive.

Best

Cheers mate. Unfortunately the dealer’s said that without being able to see or prove the fault themselves, they can’t replace the sensor.

To be fair I drove it home earlier and it felt flawless.

The dealer says that if they did replace the sensor without reason, and the ABS went anyway, they risk their warranty insurer claiming they misdiagnosed it, and wouldn’t pay out.

I didn’t buy it new though (2017 model) and it’s still under warranty for over a year, so if the ABS does go they’ve assured me it’ll be covered under that.

Sounds pretty daft to me, but I guess it’s a waiting game 🥴

[Wiseowl]

Thanks to all the advice here! I posted on 21 April as my 2016 A4 Avant showed same fault. Local Audi dealer couldn’t fix it till June(!) unless I got the car ‘recovered’ to them by Audi Assist (AA). Following advice from this forum, I phoned Audi Assist who attended the car on my drive within the hour. The guy hadn’t got the part, was aware there’d been several of these issues, went away to order it. Had to be back-ordered so he made a date to come back & fix abt 10 days later. He did, so helpful, and only cost me £74!! If I’d gone to Audi dealer they wanted it for 48 hours, so imagine what that would have cost! Thanks to all here, & my advice is keep your membership of Audi Assist - I’d also extended my warranty which helped as well😉…

[liquid]

I just want to thank this Forum for the information given, I replaced my sensor today & both faults have disappeared ! 

[Steve Q]

3 hours ago, liquid said:

I just want to thank this Forum for the information given, I replaced my sensor today & both faults have disappeared ! 

So glad the forum has helped you resolve the problem 🙂

[RossMcC]

Thanks all - just replaced the brake booster pressure sensor on my A4 B9 - latest Part # 5Q0 906 207 A - hope it lasts longer than the original! 

My car experienced the problem Brake Servo Restricted + Auto Stop / Start Disabled today at 3pm, and thanks to this website I'd found the problem, and fitted the replacement part by 5pm.  The result = problem solved. :-)  Excellent. 

[DevQ7]

Hi All,

I have a similar issue but maybe not as simple. I have a Q7 which i bought from Audi 2nd hand and 2 weeks after my 12 month warranty ran out I had a warning sign come up saying 'Brake Servo Restricted - continue to drive but visit garage' or words to that effect. Unfortunately due to personal reasons I failed to purchase extended warranty and also didn't manage to get the car into the garage for a few weeks. The warning sign then changed to 'Brake: Fault - Stop Immediately' - or words to that effect and comes up every time the ignition is turned on. A few days later the brakes started to crunch every time they were applied and I eventually managed to hand it into my local garage who changed the brake servo sensor which cleared up the crunching but the warning sign still remains. They said they couldn't clear the fault and it seems like the ABS unit has 'clocked itself out' and will need replacing. I took it to Audi to look into and they diagnosed it as a possible faulty brake pressure sensor which they suggested to replace at a cost of £185 and if that doesn't work then it'll need a new ABS unit and hydraulic part to fix the issue at a cost of around £3000. When i told them the sensor has been replaced recently the only option they gave was therefore to replace the ABS unit.

The sensor that my garage replaced is branded Sensata with OEM number 5QA 906 207A, which i'm assuming is ok to use?! I cant see how Audi changing the sensor will correct the issue as I've had 2 independent mechanics (one of whom used to work for Audi) say that the ABS control unit needs replacing but may be able to get fixed for a few hundred quid? has anyone heard of this? I really don't want to spend £3k if I don't have to. 

Your help and advice in this is very much appreciated.

Look forward to hearing from you

Dev

 

[DevQ7]

On 5/7/2021 at 12:56 PM, paul-k said:

Despite being quoted 6 to 10 days, the sensor arrived yesterday and I fitted it this morning.  Message now cleared!  Thanks again to the guy who recommended doing it myself, saved me well over 100 quid!

Hi Paul,

Glad to hear your issue got fixed. When you say you didn't want to run into the ABS issue - what do you mean exactly? i fear this is what I have done unknowingly and now looks like I need my ABS control unit replaced?

Dev

[PHB]

I am new to this forum so I may be in the wrong area. I have the warning light "Brake Servo Restricted" come on. Brake can only really be used if pressed slowly, if more pressure is applied they almost lock up and the ABS activates I think.

The main dealer can not look at the car until July, it has only done 24,000 miles and just over 3 years old. They suggested I may need a complete new ABS system but I have read on this post that other people have just had the "booster pressure sensor" replaced, am I correct?

Any help would be appreciated.

[Steve Q]

1 hour ago, PHB said:

I am new to this forum so I may be in the wrong area. I have the warning light "Brake Servo Restricted" come on. Brake can only really be used if pressed slowly, if more pressure is applied they almost lock up and the ABS activates I think.

The main dealer can not look at the car until July, it has only done 24,000 miles and just over 3 years old. They suggested I may need a complete new ABS system but I have read on this post that other people have just had the "booster pressure sensor" replaced, am I correct?

Any help would be appreciated.

I'd start off with the sensor as it's the common issue. 

[PHB]

Thanks Steve. Is that the sensor within the ABS unit or somewhere else.

[TheITGuy]

It's the brake servo pressure sensor that needs replacing.  Don't drive the car too much before replacing, as with it not working, the car uses the ABS to assist braking, which after a while results in the need to pay a hefty bill to replace ABS components.

[PHB]

Thanks Glen. I read one post that suggests on the 2017 model the complete ABS pump has to be replaced as the sensor is an integral  part of the unit and can not be replaced. Do you know if this is the fact.

[PHB]

Very strange, just went to drive it to the garage this morning and it is working as normal and the warning has disappeared. Left it with the garage for them to check the fault history. I could not find a local Audi garage that could look at it until July so I have gone to general garage.

[Steve Q]

1 hour ago, PHB said:

Very strange, just went to drive it to the garage this morning and it is working as normal and the warning has disappeared. Left it with the garage for them to check the fault history. I could not find a local Audi garage that could look at it until July so I have gone to general garage.

Will be interesting to see what they find on The diagnostic check. Please keep us posted

[Marc69]

Hi I am new to this as I have just joined I bought a 66 plate A4avant 2.0TDI I have had the same warnings come on the dash then it went away for a week then it came back saying stop safely and don’t drive in words to that effect. I have been reading all about it why have Audi not done a recall 

[PHB]

I agree, this should be a Audi recall, it must be a safety issue if it can causes a brake fault. The garage that is investigating the problem for me has been told that the car should not be driven as it could lock up the ABS unit and if this happens the complete unit would need to be replaced. The unit is £1500 plus fitting etc. The sensor which needs replacing is on back order from Germany as there has been such demand for them in the UK, that tells the story.

[Marc69]

Can anyone help I need this part desperately i have a 66 plate A4 Avant 2.0 TDI 190 HP not sure the correct part number I have seen they sell on eBay but not sure of the correct part number. And is it an easy fix any help would be greatly appreciate thanks Marc

[Norm Rees]

Apparently it is an easy fix. Unclip the existing sensor and replace. 
 

me being not mechanically gifted got the garage to do it. 
 

now I’ve seen how simple it is I could have done it.