Hi, looking for some help if anyone has had a similar experience. Sorry bit long winded

2018 Audi A6 C8 automatic, 78000 miles

I was driving the car through my local town just over a week ago and the car 'jerked' which kind of threw me forward a bit, if you can imagine someone dabbing the brake with out you expecting it, that's how much it threw me forward. Only lasts a split second then it did it again and after that it stopped for the rest of the journey. Car changes gear as normal on upshift and downshift. The car continued to do this the next day and then has now done it everyday on at least one journey. It usually happens within the first 20 minutes into a journey, not sure if that's related. It's unpredictable when it's going to do it but when it does the revs drop for a split second as if the car is loading power. On Tuesday past I was in a forest park with my family and I was driving up a steep hill and it did it twice in the space of a few seconds so two jerks forward then the car died, lost power, yellow warning light on dash saying drive system fault contact workshop. It was as if it went into limp mode. It was in 'D' but wouldn't move. So I turned the car off and on and warning light was away and car drove off as normal. It's very strange. I drove he car yesterday to work and back which is mostly motorway and it never missed a beat but yet it started doing it again last night on a different journey to the town. Could this be a gearbox issue? I got the car with 42k miles ,got it booked in to the local Audi dealer at 43k miles for gearbox service then it's just after another gearbox service at 75k miles at the end of June. The car got a timing belt and water pump done during the week as I had a water pump leak. I got that guy to plug it in but he said it showed up no fault codes. I am getting another guy to plug it in this weekend hopefully who has a better computer I believe from what he says.

 

Any help appreciated.

Hi Paul

I am absolutely not a mechnic, but when I was researching the issues of my own car, Audi A6, C8 40 Tfsi , 2022 Engine Management Light.

Audi said, it may be a throttle valve setting issue. If you Google it, many, almost all of the symptoms you have described come up via AI.

Maybe worth looking into.

Edited August 20, 2025Aug 20 by JimL

Needs scanned with VCDS ideally. Take it this is Stronic 7-speed? If it's had two services it should be in great condition.

If it's a wet-clutch there are gear adaptions and it might be out of sync. S-Tronic should be serviced every 38k miles, so servicing is on the money.

Double-check the gearbox by looking at the codes on the build sticker (either in spare wheel well or on service book inside cover) - if that's even still a thing!

There are some videos on YouTube with VCDS, but key thing is to know the gearbox first and see what you're dealing with.

Incidentally - if you are technical, then VCDS can be obtained from Gendan via Rosstech. You'll need an old laptop using probably Windows 10, especially if you're sticking with the brand long-term. Bear in mind a main dealer will charge £150 just to scan. Just a thought. 3 VIN version is fine. 

17 hours ago, JimL said:

Hi Paul

I am absolutely not a mechnic, but when I was researching the issues of my own car, Audi A6, C8 40 Tfsi , 2022 Engine Management Light.

Audi said, it may be a throttle valve setting issue. If you Google it, many, almost all of the symptoms you have described come up via AI.

Maybe worth looking into.

Thanks Jim, I will read up on this to see if it could be related

17 hours ago, spartacus 68 said:

Needs scanned with VCDS ideally. Take it this is Stronic 7-speed? If it's had two services it should be in great condition.

If it's a wet-clutch there are gear adaptions and it might be out of sync. S-Tronic should be serviced every 38k miles, so servicing is on the money.

Double-check the gearbox by looking at the codes on the build sticker (either in spare wheel well or on service book inside cover) - if that's even still a thing!

There are some videos on YouTube with VCDS, but key thing is to know the gearbox first and see what you're dealing with.

Incidentally - if you are technical, then VCDS can be obtained from Gendan via Rosstech. You'll need an old laptop using probably Windows 10, especially if you're sticking with the brand long-term. Bear in mind a main dealer will charge £150 just to scan. Just a thought. 3 VIN version is fine. 

You are exactly right, the main dealer is looking £150 for a one hour diagnostic check then £204/he for every hour after that if I want them to look into if further.

It is 7 speed stronic. I got two friends to plug their computers into it but it didn't throw up any fault codes. Iwas wondering could it be anything to do with the oil level in the gearbox, maybe too much or two little? But then I'm thinking the gearbox was serviced at 75k miles and this started happening at just over 77k miles of it was oil level after the service should it have started happening straight away and not two thousand miles after service.

Hi 

Did you get any further with finding out what the problem is ? I am having the exact same issue with my Q2 . Can't figure it out 

On 8/21/2025 at 2:07 PM, PaulF214 said:

You are exactly right, the main dealer is looking £150 for a one hour diagnostic check then £204/he for every hour after that if I want them to look into if further.

It is 7 speed stronic. I got two friends to plug their computers into it but it didn't throw up any fault codes. Iwas wondering could it be anything to do with the oil level in the gearbox, maybe too much or two little? But then I'm thinking the gearbox was serviced at 75k miles and this started happening at just over 77k miles of it was oil level after the service should it have started happening straight away and not two thousand miles after service.

Not all car diagnostics are the same and it may not throw a code. If it’s VCDS, run gearbox adaption for clutch calibration. There are videos on YouTube, or take it to a specialist, and that doesn’t necessarily mean the main dealer.

Last service at 75k, then there’s a process to filling S Tronic, so suspect all is well regards levels.

6 hours ago, G-Ray181 said:

Hi 

Did you get any further with finding out what the problem is ? I am having the exact same issue with my Q2 . Can't figure it out 

Hi, no I have not got any further. Been trying to get in contact with a local Audi specialist so he has said he will phone me tomorrow and I would imagine he might want the car down to see if he can diagnose it. Will keep you posted. 

Hi, did you have any success with this yet? I have the exact same issue. First happened on 02AUG. Was pretty intermittent but has gotten progressively more frequent since then. Often just a single jerk, with no warning lights. Or codes, that I can read anyway with VCDS (although mine is older model and cant communicate fully with the ECU). Audi scanned the car as it was in for a service (mid Aug) and no error codes showed.

Car has full audi service history incl stronic gearbox services.  I'm going to try get the car back to Audi tomorrow, as last friday, the car jerked about 4 time in quick succession, followed by a drive system & stop start fault + loss of power. I turned it off and back on and was perfect!

Its very frustrating. I also believed it was occurring shorty after initial startup as it happened twice on the same section of road that I drive every day. But has since occurred well into a long drive. I've also tested with all systems disabled indivdually, lane assist, stop start, efficient coast, gearbox in manual... etc... the issue can still occur. Has happened at high & low speeds.

I have a good mech/elect background as an engineer and have always worked on my own cars, until this A6, so its not my first rodeo in troubleshooting! But this has me stumped so far. Hopefully we can help each other out if we learn anything. I'll keep you posted on what Audi say to me this week. 

Hi, I am not really any further forward. Definitely sounds like your car is doing the same as mine. The car was in last week with my local Audi specialist who has a very good reputation. They changed the oil in the gearbox so they knew it was at the correct level, bearing in mind it had only been changed 3000 mile ago by a local Audi dealer. He said they adjusted a few settings, not too sure what but unfortunately the issue is still in the car. So we can rule out oil level. What we do know is that it doesn't jerk when the car is cold and it doesn't tend to do it on a journey when the car is started from cold. So if I drove a 100 mile journey from cold it might not do it but if I stop, turn the car off  and then back on again after saying twenty minutes it will do it quite bad.  The car almost had no power last night pulling off a roundabout in my local town in second gear anytime I pressed the throttle slightly it would barley move I had to pull in. 

Not sure what my next move is. The Audi specialist said he would try and do some homework on it and try and find a solution he is convinced it's electrical but because it's not throwing up any codes on his computer it's finding the right place to look. It is frustrating not knowing how to fix it or what to replace as it could be any one of them things. I have a video I took this evening driving on a country road if it attaches have a look at the rev needle and that's only me pressing the accelerator slightly and while it's doing that the car is struggling.

Latest on this for me is that, audi found a leaking waterpump. Its leaked onto the timing belt, they were suspecting potential timing issues because of this leading to the jerking issue. I didn't buy that as a fix but needed to be sorted none the less. Surprisingly they rang today to say it didn't sort it. So now tracking a fault related to crank shaft position sensor, more plausible I think.  Does anyone know of a recall on waterpumps in Europe? I see there is a class action lawsuit in the states and people are having costs covered for waterpumps on various tdi engines from Audi. 

1 minute ago, irishrio said:

Latest on this for me is that, audi found a leaking waterpump. Its leaked onto the timing belt, they were suspecting potential timing issues because of this leading to the jerking issue. I didn't buy that as a fix but needed to be sorted none the less. Surprisingly they rang today to say it didn't sort it. So now tracking a fault related to crank shaft position sensor, more plausible I think.  Does anyone know of a recall on waterpumps in Europe? I see there is a class action lawsuit in the states and people are having costs covered for waterpumps on various tdi engines from Audi. 

I had a leaking water pump in mine from about April time, it was only a small leak so I just kept topping up until I got it fixed mid August. I agree this didn't have any affect on my timing as the car drove probably 6 or 7000 miles before the jerking begun. I did read a similar forum about a guy who has similar issues as ours and his was down to a crank position sensor. I am thinking about buying one for my car to see if it does anything and if not it will at least rule that out as I think they aren't overly dear to buy. The leaky water pumps seem to very common, guy in work has only 40k mile on an A6 and his was leaking.

3 hours ago, irishrio said:

Does anyone know of a recall on waterpumps in Europe? I see there is a class action lawsuit in the states and people are having costs covered for waterpumps on various tdi engines from Audi. 

No recall that I know of. Audi's recommendation for timing belt and water pump renewal used to be about 70000 miles, but has been increased to effectively never, which I and others here believe was a mistake given the known vulnerability of the belt, and the sometimes catastrophic consequences of its failure.

4 hours ago, PaulF214 said:

I had a leaking water pump in mine from about April time, it was only a small leak so I just kept topping up until I got it fixed mid August. I agree this didn't have any affect on my timing as the car drove probably 6 or 7000 miles before the jerking begun. I did read a similar forum about a guy who has similar issues as ours and his was down to a crank position sensor. I am thinking about buying one for my car to see if it does anything and if not it will at least rule that out as I think they aren't overly dear to buy. The leaky water pumps seem to very common, guy in work has only 40k mile on an A6 and his was leaking.

Hi the crank position sensor is at the back of the engine where the gearbox meets the engine, bit of a sod to get to but doable, then again looking at your symptoms I would be inclined to look at the DMF or Mechatronics unit which would be favourite as these things only ever throw a code when they are really knackered, I understand the process that replacing the position sensor is the cheapest option to start with and hopefully that will cure it.

Steve.

3 hours ago, Stevey Y said:

Hi the crank position sensor is at the back of the engine where the gearbox meets the engine, bit of a sod to get to but doable, then again looking at your symptoms I would be inclined to look at the DMF or Mechatronics unit which would be favourite as these things only ever throw a code when they are really knackered, I understand the process that replacing the position sensor is the cheapest option to start with and hopefully that will cure it.

Steve.

Thanks Steve, will hopefully try and get a hunt for it this weekend to see if I can find it.

Same issue, any updates?

 

My 2017 A6 started stalling out of nowhere after having the timing belt replaced. No faults showing when plugged in just stalls from time to time out of nowhere, no warning lights. Have had it with two mechanics and an ‘Audi specialist’ yet they cannot determine the issue at hand. Car was remapped two years ago and drove like new ever since. Anyone Experiance anything like this and can advise please, waiting over two months now trying to figure this out

Hello Laura,

So has it been returned to the garage who changed the cambelt , if as you indicate, the car was performing fine before?

Has any of the 3 garages plugged this into an acceptable diagnostic system?

Sounds as if something has been disturbed/ damaged if the problem was coincident with fitting the new belt - assuming the belt was correctly fitted.

Regards,

Gareth.

48 minutes ago, Magnet said:

Hello Laura,

So has it been returned to the garage who changed the cambelt , if as you indicate, the car was performing fine before?

Has any of the 3 garages plugged this into an acceptable diagnostic system?

Sounds as if something has been disturbed/ damaged if the problem was coincident with fitting the new belt - assuming the belt was correctly fitted.

Regards,

Gareth.

Hi Gareth 

yes it’s been there, now for second time, they’ve plugged it into computer and nothing showing. Extremely frustrating, it’s an amazing car but am kinda afraid to drive it now with this intermittent issue. Same garage have been servicing it the past four years and no issues.

Hi All, sorry ive been away past two weeks so didn't get a chance to post. Ive a couple of hundred km's on my car now since replacing the crankshaft pos sensor. The issue is resolved in my opinion and thankfully to a plausible conclusion in terms of that sensor. 

I've no further update from my side. Getting the crank position sensor fitted tomorrow evening to see if this helps it. If not, it will rule it out and back to the drawing board. Took this video with a bit of sound, this is me trying to turn into a side road, you can hear a clunking noise as the rev needle is moving up and down. 

Hi Paul, did the Camshaft pos sensor work for you also? I have the exact same problem you describe although can't see the videos now? From other forums it could be low/weak battery issue apparently? My gearbox is overdue a service so might do that anyway. I do have VCDS and may do the clutch calibration a few suggested but I don't think that will fix it. I'm guessing it is the crankshaft sensor most likely?

Hi, just an update on my own car. Crank position sensor was fitted last week and I have done a few hundred miles since and this seems to have fixed the problem I was having. So far so good. I had bought a sensor at £30 it wasnt a genuine one and a local German car specialist fitted it for me took a couple of hours. Total cost for labour was £150. Definitely worth trying if you are experiencing similar issues as mine.

The jerkiness is a known issue. Besides the sensor fix you implemented, it can also be a sign of a failing mechatronic, again known issue. Not logging the fault in the ECU/TCU is also a known issue. If you are a new car owner, Audi won't replace the mechatronic unit unless the fault is logged despite the fact that there is a documented fault where the faults aren't logged...

On 10/30/2025 at 8:34 AM, PaulF214 said:

Hi, just an update on my own car. Crank position sensor was fitted last week and I have done a few hundred miles since and this seems to have fixed the problem I was having. So far so good. I had bought a sensor at £30 it wasnt a genuine one and a local German car specialist fitted it for me took a couple of hours. Total cost for labour was £150. Definitely worth trying if you are experiencing similar issues as mine.

Hello mate, I’m having the same issue currently. My local specialist is saying the gearbox has to come off for this but your labour was cheap? Any chance I can be in touch

Kind regards

Has.

Paul has not returned to the forum since October last year. A PM might get to him, or it might not.