2021 RS6 Died on the Road

[Ven2323]

'21 RS6, took delivery Jan 2021, generator failed last week at 44k miles. This has been my daily driver, Unitronic tune with catless downpipes; and the car has been nothing but solid. I guess the generator failure seemed bound to happen after reading all this. Worth the headache to drive this car everyday IMO. And now I know the warning signs for my wife's car.

[FBAnder]

'21 RS6, took delivery Jan 2021, generator failed last week at 44k miles. This has been my daily driver, Unitronic tune with catless downpipes; and the car has been nothing but solid. I guess the generator failure seemed bound to happen after reading all this. Worth the headache to drive this car everyday IMO. And now I know the warning signs for my wife's car.

44k! Might be the record so far.

[johnpark287]

Do these issues target particular model years, or are they inevitable for all RS6 vehicles over time? Reading through this thread is making me feel uneasy. 😢

[SwissMTNAlien]

Seems to affect 2021 and 2022 RS6 for sure. Waiting to hear if any 2023 RS6 experience this issue...

[brad65ford]

While there can be so many things to be concerned with with any car seems this is the major one for this one. Did I hear correctly its a 5-6k job on average cost for repair? can anyone share photos of the part and or photos of the job itself?

[RMode]

While there can be so many things to be concerned with with any car seems this is the major one for this one. Did I hear correctly its a 5-6k job on average cost for repair? can anyone share photos of the part and or photos of the job itself?

It’s covered by audi. I have yet to hear of anyone paying out of pocket


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[OneFastBMW]

It’s covered by audi. I have yet to hear of anyone paying out of pocket


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People who have tunes have paid out of pocket for the repair.

[RMode]

People who have tunes have paid out of pocket for the repair.

I should I clarify - yes, you mod anything on the ecu side, you risk your warranty. How it’s always been, and always will be, unless the dealer is ok with it up front. It’s an inherent risk. Or, you learn to work on your own cars and mod to your hearts content.


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[brad65ford]

I should I clarify - yes, you mod anything on the ecu side, you risk your warranty. How it’s always been, and always will be, unless the dealer is ok with it up front. It’s an inherent risk. Or, you learn to work on your own cars and mod to your hearts content.


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This.

[johnpark287]

Not sure if I want to take delivery of my RS6 now.. It should be arriving in a few weeks but man.. Not sure if I want to be driving around with the fear that it will one day give out..

[brad65ford]

Thought the same but figured life is short.

[FBAnder]

All the symptoms are in this thread. Should at least prevent you from getting stranded in the middle of the road somewhere dangerous as there IS time between symptoms start and dead car.

[brad65ford]

I just want to see pictures of the process lol

[Ven2323]

After initial indicator lights came on, my car went about 25 miles before full shutdown; had i known where it was heading (i didn't) i would have pulled into a safe place as soon as the battery indicator turned red (i went about 2.5 miles on red indicators and got stranded at a light a mile from my house). I was able to charge the battery with cables to get home and then did full charge overnight. On a full charge, the car will repeat the same pattern, at least it did for me. So hopefully you live within 20 miles of a dealer!! Or plan accordingly.

[johnpark287]

After initial indicator lights came on, my car went about 25 miles before full shutdown; had i known where it was heading (i didn't) i would have pulled into a safe place as soon as the battery indicator turned red (i went about 2.5 miles on red indicators and got stranded at a light a mile from my house). I was able to charge the battery with cables to get home and then did full charge overnight. On a full charge, the car will repeat the same pattern, at least it did for me. So hopefully you live within 20 miles of a dealer!! Or plan accordingly.

Yikes... what a disaster... Anyone know if the performance variants have this problem resolved ie. use of revised alternator etc or is it the same?

[BoGs]

Not sure if I want to take delivery of my RS6 now.. It should be arriving in a few weeks but man.. Not sure if I want to be driving around with the fear that it will one day give out..

I asked my dealership if this is still a problem. Supposedly 2023 have a new alternator on them (recent 2023) and "should" be fixed. Time will tell. I just got my VIN 2 weeks ago :)

[pwdrskr]

'21 RS6, took delivery Jan 2021, generator failed last week at 44k miles. This has been my daily driver, Unitronic tune with catless downpipes; and the car has been nothing but solid. I guess the generator failure seemed bound to happen after reading all this. Worth the headache to drive this car everyday IMO. And now I know the warning signs for my wife's car.

It’s covered by audi. I have yet to hear of anyone paying out of pocket


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People who have tunes have paid out of pocket for the repair.

I guess I'm still in the "safe" zone with only ~11k miles.

I'm curious if anyone with a tune, in particular a piggy back, has had the alternator failure repaired by Audi. Also curious if someone had APR+, had the alternator fail, were denied warranty coverage by Audi, but had repairs covered by the APR+ warranty.

[johnpark287]

I asked my dealership if this is still a problem. Supposedly 2023 have a new alternator on them (recent 2023) and "should" be fixed. Time will tell. I just got my VIN 2 weeks ago :)

This is the only positive thing I have read on this forum today .. What hat would be considered a recent 2023 build? My production was completed in June 2023..

[brad65ford]

This is the only positive thing I have read on this forum today .. What hat would be considered a recent 2023 build? My production was completed in June 2023..

I've also heard this isn't true, all new performance models are going to have the same part number too.

if this subject is the only/main concerned about this platform there should be a sticky with a poll to share how many have had it.

[SwissMTNAlien]

Thought the same but figured life is short.

Same here!

I read about the alternator issue a ton before pulling the trigger on my 2023 RS6 and almost decided to go with a M3 instead. I was told by two different dealers that the newer 2023 models shouldn’t be affected… however I won’t be shocked if they were lying to make a sale. This issue is the main reason I decided to buy a new 2023 instead of a used 2021 or 2022 like I was initially planning. Even if my ‘23 goes down with this issue one day, I have zero regrets about buying it.

[brad65ford]

Same here!

I read about the alternator issue a ton before pulling the trigger on my 2023 RS6 and almost decided to go with a M3 instead. I was told by two different dealers that the newer 2023 models shouldn’t be affected… however I won’t be shocked if they were lying to make a sale. This issue is the main reason I decided to buy a new 2023 instead of a used 2021 or 2022 like I was initially planning. Even if my ‘23 goes down with this issue one day, I have zero regrets about buying it.

Funny just swap the g80 for the c8 rs6. Was a hell of a great platform wouldn't be up set ever going back to it. Just wanted a change, night and day difference between them.

The dealer that we purchased our 23 rs6 from seemed pretty honest, he had a customer that purchased a sq8 and had the alternator go. He said its fairly quick turn around now compared to months go. I ask about our new 23 rs6 we were purchasing and if they changed or updated any part and he said they are all the same and its surely possible it can go. I think the fear of it crapping out is one issue, and the other is for the guys tuning their cars that it will be voided warranty and not fixed. Personally I think regardless if its tuned it should be fix since its not related.

[SwissMTNAlien]

Funny just swap the g80 for the c8 rs6. Was a hell of a great platform wouldn't be up set ever going back to it. Just wanted a change, night and day difference between them.

The dealer that we purchased our 23 rs6 from seemed pretty honest, he had a customer that purchased a sq8 and had the alternator go. He said its fairly quick turn around now compared to months go. I ask about our new 23 rs6 we were purchasing and if they changed or updated any part and he said they are all the same and its surely possible it can go. I think the fear of it crapping out is one issue, and the other is for the guys tuning their cars that it will be voided warranty and not fixed. Personally I think regardless if its tuned it should be fix since its not related.

Glad to hear the turnaround is faster now for the part. Also 100% agree that it should be covered for tuned cars, it’s an established issue affecting a ton of stock tune cars, but sounds like that’s not the case for most dealers. I’m really tempted to tune mine but worried about getting stuck with the alternator bill if it goes.

[johnpark287]

I have a quick question for current or past owners of RS6/RS7 models. Regarding the alternator failure issue, is this something that will inevitably occur in all RS6 and RS7 vehicles, or is it more of a possibility that "might" happen? I'm curious because it is sounding like a regular maintenance matter where the alternator simply needs replacement once it gives out lol

[FBAnder]

I have a quick question for current or past owners of RS6/RS7 models. Regarding the alternator failure issue, is this something that will inevitably occur in all RS6 and RS7 vehicles, or is it more of a possibility that "might" happen? I'm curious because it is sounding like a regular maintenance matter where the alternator simply needs replacement once it gives out lol

No one knows. Of course anything can fail on any car. Everything will eventually fail on every car. The question with the alternator is how long will it take and we have seen a range from 2k miles to 44k miles...doesn't seem to be any rhyme or reason why some make it longer than others. Folks have theorized...stop/start usage seems to be the most common but really nothing definitive has emerged.

The issue is prevalent enough that Audi extended the warranty on this part fairly significantly...but no recall has been issued.

Clear as mud?

[johnpark287]

No one knows. Of course anything can fail on any car. Everything will eventually fail on every car. The question with the alternator is how long will it take and we have seen a range from 2k miles to 44k miles...doesn't seem to be any rhyme or reason why some make it longer than others. Folks have theorized...stop/start usage seems to be the most common but really nothing definitive has emerged.

The issue is prevalent enough that Audi extended the warranty on this part fairly significantly...but no recall has been issued.

Clear as mud?

Thanks. I guess I will just take the delivery and take my chances!

[brad65ford]

Been trying to find actual video or photos of what these look like and or the job at hand for reference. Is this it?
https://www.youtube.com/watch?v=RkOG9FiJVKc
Also was is the cause, something about coolant? Assuming it has water cooling and there is a connection that is failing causing the alternator to burn out?
https://www.youtube.com/watch?v=CRyDI3sCXyM

https://www.audizine.com/forum/showt...or-issue-RS6-7

https://transistor-man.com/audi_48v.html

[Ven2323]

Start/Stop is turned off every time I get in the car; not sure if it helped mine get to 44k before failure; but I guess it’s a possibility

[OneFastBMW]

For anyone curious, here is an explanation of why the symptoms appear as they do, at least in the RS6/RS7, and what to do if it happens (last paragraph if that is all you care about). Other Audi vehicles using the 48v system may be a little different. This isn’t a description of why the alternator fails, but when it fails why things happen as they do and what to do.

Background of how the system operates:
The only way that the engine can generate electrical power is through the 48v belt starter generator (“BSG”). The BSG only has 48v windings and there is no other 12v charging system directly attached to the engine. The vehicle has two discrete DC power system, one operating at 48v and one running at 12v. There is a 48v battery under the trunk directly attached to the BSG and a DC-DC converter. The DC-DC converter is pretty powerful and is used to charge a relatively small (for the size of vehicle) 12v battery. I think it is a 68ah 12v battery. The DC-DC converter is actually bi-directional meaning that it can convert 48v to 12v or step 12c up to 48v. This is important because it means that a normal 12v charger will charge the 48v battery, but the DC-DC converter will not feed the 48v battery until the 12v battery is 100% full.

The only thing that is connected to the 48v system is the BSG, the 48v battery, and the DC-DC converter. There are NO OTHER 48v systems in the car. On other Audi models the 48v system may have things like active suspension or the AC on the 48v system, but not the C8 RS6/RS7. This means that everything in the vehicle is run off of the 12v system with a relatively small battery. This battery is always being charged by the DC-DC converter. I think it is something like a 100 amp fuse between the two, so the DC-DC converter can send some serious power to the 12v battery.

Once the BSG stops working there is no longer any ability for the engine to generate electrical power. The DC-DC converter will continue to supply power to the 12v battery as it depletes the 48v battery. Once the voltage of the 48v battery packs drops below a certain voltage the DC-DC converter will stop supplying the 12v system. The system realizes this and starts to shed 12v power draws as much as possible. This is why we get the “Christmas tree” of warnings as the system turns off all these system to save power. Since the 12v battery is relative small, it doesn’t last very long. About 30 minutes of driving it seems.

The vehicle does have a “normal” 12v starter on the flex plate in addition to the 48v BSG. The 12v starter is used to start the engine when the oil temp is below 45C (about 113F), so as long as the 12v battery has enough juice, you can start the car. You can also “supplement” the on-board 12v battery with a jump pack to give you more time. When charging the 12v battery, DO NOT connect the charger to the 12v battery itself. This will confuse the car. Only use the charging posts under the hood. There is a shunt installed on the negative terminal of the 12v battery that monitors current in and out of the battery. If the charger is connected to the battery itself, the car will only see current going out, and not back in. By connecting a charger to the charging posts under the hood, the car will see current going back into the 12v battery.

If you have this failure, you can drive for a little bit (maybe up to 30 minutes) and then you need to charge the 12v battery back up. This can be done with another car and jumper cables, a large lead acid jump pack (I wouldn’t use one of the lithium jump packs for this since they are not designed for sustained high-current discharge), or a standard 12v charger. If possible, don’t shut off the engine. It technically can start with the BSG failed, but I don’t know if the computers will let it. Repeated this process will allow you to drive the car as far as you need to in order to get it to the dealer.

What to Do if This Happens:
So if this happens to you, plan A is head straight to the dealership if you are close and do not turn off the car until you get there. If you are more than 20 minutes from the dealership Plan B is to call a buddy and have them come meet you ASAP with jumper cables. You need to charge back up the 12v battery before it dies. You can “hop-scotch” along depleting then charging the 12v battery 20 minutes at a time until you get to the dealer. Plan C is to find the closest service station or parts store (like an AutoZone) with a high amp charger. Hook it up right as you get there and let the 12v battery fully charge back up. Repeat plan A, B, or C as necessary.

Good luck,
Paul

[brad65ford]

almost need to carry around another 12v battery with long enough wires just in case lol. Sounds like there needs to be a kit to remove these 48V systems, like that will ever happen. Joking aside. One of the things that I noticed when cruising on the highway is when you let off the gas how the car keeps moving, this is all the 48V system working.

[FBAnder]

almost need to carry around another 12v battery with long enough wires just in case lol. Sounds like there needs to be a kit to remove these 48V systems, like that will ever happen. Joking aside. One of the things that I noticed when cruising on the highway is when you let off the gas how the car keeps moving, this is all the 48V system working.

I'm always debating on getting a high amp portable charger and keeping it in the hatch lol. Trouble is you generally need to plug those in for input power...the cost otherwise starts to get obscene as a backup for a failed alternator.

[Gecon]

It's a great car! Don't worry about the BSG failure, and I have heard that they are readily available these days. I have a 2021 with 20k miles and no problem yet. perhaps it fails someday and I will be a bit grumpy when I am waiting for a tow truck and then getting it serviced. But I know when I get back in the rocket ship, all will be forgotten quickly!

I also have read on another thread about successfully charging the battery when the BSG failed. OneFastBMW gave a great write up. based on the other post, you will know when it happens because you will slowly get one warning after another about system failures.

someone else was worried about tuning the car and then having this potential failure. I think a BSG failure is the least thing to worry about. lots of other more expensive items can fail. if you are worried, look into the Burger Motorsport JB4 unit that is a piggy back to the ECM. you connect the 4 boost pressure sensors to it and it basically tricks the ECM into thinking there is less boost pressure than actual. If you have a failure, you just remove it. it does not leave a direct trace. However, it could take an hour or two to remove it and if you were to damage something significant, Audi may look at all the engine data that is stored and wonder why the mass air flow meter indicates the engine was getting far more air than possible...among a few things. of course they could still not prove you did anything!

EDIT: i meant to answer JohnPark287

[johnpark287]

It's a great car! Don't worry about the BSG failure, and I have heard that they are readily available these days. I have a 2021 with 20k miles and no problem yet. perhaps it fails someday and I will be a bit grumpy when I am waiting for a tow truck and then getting it serviced. But I know when I get back in the rocket ship, all will be forgotten quickly!

I also have read on another thread about successfully charging the battery when the BSG failed. OneFastBMW gave a great write up. based on the other post, you will know when it happens because you will slowly get one warning after another about system failures.

someone else was worried about tuning the car and then having this potential failure. I think a BSG failure is the least thing to worry about. lots of other more expensive items can fail. if you are worried, look into the Burger Motorsport JB4 unit that is a piggy back to the ECM. you connect the 4 boost pressure sensors to it and it basically tricks the ECM into thinking there is less boost pressure than actual. If you have a failure, you just remove it. it does not leave a direct trace. However, it could take an hour or two to remove it and if you were to damage something significant, Audi may look at all the engine data that is stored and wonder why the mass air flow meter indicates the engine was getting far more air than possible...among a few things. of course they could still not prove you did anything!

EDIT: i meant to answer JohnPark287

Thank you sir. Much appreciated!

[Hkc]

I mean, you can say it’s a great car, which it is, but to say not to worry about the failure is kind of crazy.

I drive this car cross country. I bought it for road tripping. I’m looking to trade it now bc audi won’t just fix the issue and instead I need to wait until I’m stranded in the mountains of Colorado attempting to jump start this giant German pos every 20 min to make it to a dealer? It’s insane that the solution is wait until it fails and then we will replace it. How can you just let the consumer drive with anxiety just waiting for the car to leave you stranded? Crazy for a six figure car.

[RMode]

I mean, you can say it’s a great car, which it is, but to say not to worry about the failure is kind of crazy.

I drive this car cross country. I bought it for road tripping. I’m looking to trade it now bc audi won’t just fix the issue and instead I need to wait until I’m stranded in the mountains of Colorado attempting to jump start this giant German pos every 20 min to make it to a dealer? It’s insane that the solution is wait until it fails and then we will replace it. How can you just let the consumer drive with anxiety just waiting for the car to leave you stranded? Crazy for a six figure car.

Because not every car, or even a majority of the cars, ever experience the issue. The part isn’t unique to an RS, it’s used across a lot of models, and only a small fraction have had the issue.


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[Hkc]

Still doesn’t change the issue.

Not every car? If one out of twenty cars leaves the consumer stranded and in possible danger, that’s unacceptable isn’t it? This is a major failure waiting to happen and to say no big deal, it’s just some of the cars is insane. Audi should replace the alternator since they themselves have told me it’s just a matter of time but it needs to fail first before they can act. “Just wait for your car to blow up, then we will fix it”. Lol

[Corgiman30]

I mean, you can say it’s a great car, which it is, but to say not to worry about the failure is kind of crazy.

I drive this car cross country. I bought it for road tripping. I’m looking to trade it now bc audi won’t just fix the issue and instead I need to wait until I’m stranded in the mountains of Colorado attempting to jump start this giant German pos every 20 min to make it to a dealer? It’s insane that the solution is wait until it fails and then we will replace it. How can you just let the consumer drive with anxiety just waiting for the car to leave you stranded? Crazy for a six figure car.

I got blasted for suggesting I’d be hesitant to take this car on a long trip. “Just sell it and someone will snap it up”. Had to have my hood’s PPF replaced due to rock damage and the guy asked if I’d had BSG replaced yet….

[Hkc]

I got blasted for suggesting I’d be hesitant to take this car on a long trip. “Just sell it and someone will snap it up”. Had to have my hood’s PPF replaced due to rock damage and the guy asked if I’d had BSG replaced yet….

Don’t get me wrong, it’s one of the best road tripping cars period. Comfort, capability, safety, space.

Then there’s the bsg issue lol. It’s unnerving to be driving in the middle of nowhere having this bsg crap in the back of your mind. Yet people will say not to worry about it. I mean yeah if all we did was drive in the city within a few miles of the nearest Audi then maybe not so big a deal. But something this capable deserves the open road and unfortunately that’s where i don’t trust it until they can find a permanent solution.

[RMode]

Still doesn’t change the issue.

Not every car? If one out of twenty cars leaves the consumer stranded and in possible danger, that’s unacceptable isn’t it? This is a major failure waiting to happen and to say no big deal, it’s just some of the cars is insane. Audi should replace the alternator since they themselves have told me it’s just a matter of time but it needs to fail first before they can act. “Just wait for your car to blow up, then we will fix it”. Lol

Its not one of 20, or one of 40, or even one of 100.

If it causes that much anxiety, then absolutely, sell it, and move on to something else. It's not a difficult car to get out of by any means.

This forum is a tiny scintilla of owners, let alone owners of cars that use the same alternator....those cars total hundreds of thousands.

[KRracer]

Still doesn’t change the issue.

Not every car? If one out of twenty cars leaves the consumer stranded and in possible danger, that’s unacceptable isn’t it? This is a major failure waiting to happen and to say no big deal, it’s just some of the cars is insane. Audi should replace the alternator since they themselves have told me it’s just a matter of time but it needs to fail first before they can act. “Just wait for your car to blow up, then we will fix it”. Lol

If you truly believe it is a safety hazard, start a claim with NHSTA. If they get enough complaints, they can ultimately force a recall by a manufacturer.

Otherwise, you're just making complaints to thin air here, regardless of how right you may be. Audi isn't going to spend millions of dollars to replace all these units because of some bitching forum members (no offense).


Cheers,

KR

[AZDucrdr]

Audi is not alone in their difficulties with a 48 volt system.

https://www.carscoops.com/2023/08/nh...-system-fault/