"Drive System Malfunction" - Overheat? Knock? Vaccum Leak? - 2019 B9 RS5

[TWRBO]

Hello everyone,

New the to the forum, had my '19 RS5 SB for about 3 weeks as my first Audi, at about 30,000 miles.

Overall the car seems to be in OK shape, however, twice now I've had the car go into limp mode with max RPM of 1k(!) which seems significantly lower a limit than most errors I've seen posted about.

Even compared to the infamous YouTube rocker RS5 which limited at 1.5k.

Both instances have taken place after around 30 minutes of spirited but not at all heavy cruising with some stop and go traffic. The symptoms have been the same between the two, sudden power loss coupled with a rough idle almost like it deactivated a piston or two in each bank and are firing in opposition with bad timing. Think like the old cartoons where a car is sputtering out of gas. I also noticed that my coolant temp was around 222-224F, which seems high but it would go back down to 208-ish when driving normally. It concerns me a bit since it seems a little high on average compared to what I've seen in my research. I haven't gone for VCDS yet but I may pull the trigger on that soon, I've been using a standard OBDII reader and no codes were stored.

To set the scene for the two instances:

- The first time, I had been tooling around on an errand run taking the scenic route, max speed would have been less than 60MPH and just a handful of hard accelerations. This instance threw me off with a red-herring, the error popped just as i had passed over a row of the reflective lane markers in an area undergoing construction so they were placed about a foot apart, and at 45MPH thats a lot of bumps real fast so I figured it might have thrown a sensor off. This occurred while I was slowing down to stop for a red-light. Something to be concerned about but I limped into the turn lane and just stop-started within a few seconds and it was fine.

- The second time was earlier today after again some spirited errand running but this time it occurred during a decent acceleration on an open stretch of road. Opened up to probably about 80% throttle when the error popped again but this time I'm rolling at like 70MPH and coming up to a hill. I really wasn't sure if I was going to make it over the crest but I did fortunately and was able to pull into a side street and again, stop-starting within a few seconds and the issue was resolved.

I've come across a few leads however none pertaining to the 2.9TT directly, just the 3.0 and some other models. These leads include high coolant temperature warnings due to faulty thermostats or sensors, but I haven't received that particular error at any time. Faulty coolant switching/vacuum valves, but no specific reports of this on this engine and I wasn't able to locate the particular part in the 2.9 parts list. I checked vacuum lines briefly and none appeared cracked or damaged but I didn't spray them to test as of yet. While checking the lines I also checked all the easily accessible plugs and sensors and none seemed to be loose or damaged. I'm not afraid of taking things apart, it's the reassembly that gets me

Being that I checked the easy-to-check bits, I am looking more into the ICMS misfire issues that seem to come up with similar symptoms however I don't get a CEL, code, or any indication something happened after I restart the car.

This is all a bit long but I'm trying to include as much as I can since I wasn't able to easily find another description exactly like what I've experienced, and seems somewhere between a few issues - hopefully it's not all of them

[JohnEnglish]

Isn’t it still under warranty? Take it to a dealer.

[TWRBO]

I believe so; I checked my local dealer and they're over a month out for service so I figured if it was something easy enough I'd give it a go

[c99]

No DTC ODIS/VCDS diagnostic, no answer possible.

[TWRBO]

Fair enough; I got an appointment at a dealer in the next city over tomorrow, so, fingers crossed they can identify the issue!

[TWRBO]

Just heard back - apparently, the ECU (ECM) is corrupted due to a tune that was on the car, which I didn't know was on there when I bought it. So now begins the fun; if it weren't modified, it would have been a warranty repair, but they claim the issue has rendered it unflashable and want to replace it to the tune of $3,700. I've contacted the seller, another Audi dealer, to figure out how they can make things right. The subwoofer on the car was blown too off the floor, but I didn't notice till about a week later and had already made replacement plans due to the issues I'd read about.

I'm a bit suspicious of the servicing dealer's claim that they can't re-flash it, or that this is the issue and not just a bad tune since I've heard Audi can be a bit replace-happy. As long as I'm not footing the bill, replace away! I can find the part for about $1,300 (PN: 8W0907551B8WF) from reputable sites but I heard it's another $1k-ish to program it. It seems like a case of negligence on the seller, as well as a tad bit of fraud in selling me the Audi Pure plan if it wasn't valid from the start. Now I'm also curious to see what the car will feel like WITHOUT the tune.

Sucks being stuck in an entry-spec Q5 SB in the mean time

EDIT: Looks like my car was TD1'd a month before I bought it...

Last Edit probably: Dealer has offered to buy the car back, really disappointed it couldn't be remedied otherwise but no way to get the TD1 off of it. Back to searching I guess. Will be hard to beat this one: RS Driver Asst., Dynamic and Dynamic+, Dynamic Steering, Carbon Optic, Bronze 5-arm Peak rims, tint and PPF already on it, Audi Care through 50k.

[bbowers825]

Just heard back - apparently, the ECU (ECM) is corrupted due to a tune that was on the car, which I didn't know was on there when I bought it. So now begins the fun; if it weren't modified, it would have been a warranty repair, but they claim the issue has rendered it unflashable and want to replace it to the tune of $3,700. I've contacted the seller, another Audi dealer, to figure out how they can make things right. The subwoofer on the car was blown too off the floor, but I didn't notice till about a week later and had already made replacement plans due to the issues I'd read about.

I'm a bit suspicious of the servicing dealer's claim that they can't re-flash it, or that this is the issue and not just a bad tune since I've heard Audi can be a bit replace-happy. As long as I'm not footing the bill, replace away! I can find the part for about $1,300 (PN: 8W0907551B8WF) from reputable sites but I heard it's another $1k-ish to program it. It seems like a case of negligence on the seller, as well as a tad bit of fraud in selling me the Audi Pure plan if it wasn't valid from the start. Now I'm also curious to see what the car will feel like WITHOUT the tune.

Sucks being stuck in an entry-spec Q5 SB in the mean time

EDIT: Looks like my car was TD1'd a month before I bought it...

Last Edit probably: Dealer has offered to buy the car back, really disappointed it couldn't be remedied otherwise but no way to get the TD1 off of it. Back to searching I guess. Will be hard to beat this one: RS Driver Asst., Dynamic and Dynamic+, Dynamic Steering, Carbon Optic, Bronze 5-arm Peak rims, tint and PPF already on it, Audi Care through 50k.

So did you end up returning the car back to the dealership? You mentioned the dealer offered to "buy the car back" and that's usually at some kind of bullshit restock fee upcharge on you. Just curious, good luck with the search!

[TWRBO]

Sorry yea, return or even a "void" would probably be a better descriptor; they're taking it back on goodwill since I'm not sure if they're legally required to, but they also probably don't want to find out.

Thanks, yea, the used market looks pretty barren at the moment. I guess I'll hold out for '21s and '22s, hitting the same price range over the next few months.

Edit: They said that it was a transaction "unwind", so reversing everything as if it hadn't happened. I think that even applies to the title/registration beyond them essentially "paying" me for the car.

[RUNSGR8]

I know the exact Drive System Malfunction error you're talking about. My old 2018 RS5 got that error after flashing an APR tune on it. APR immediately put out an update which fixed the issue and it never came back. Your Audi service department was definitely incorrect in saying that your ECU is "fried" and "unflashable". Sounds to me like they just wanted to make a quick extra buck off you and/or not want to risk "fixing" a TD1 car.

Either way it sounds like you returned your car, so no harm no foul. But a quick trip to a local APR dealer/mechanic would've yielded an updated tune for your car which would've prevented the error from popping up again.

[TWRBO]

It indeed had an APR tune on it, but I hadn't found any other accounts, and with APR being as well-known as they are, I assumed it was possible it was a hardware issue at that point. So thanks for replying it had been bothering me still thinking about it what could have been wrong, and if I'd repaired it, would there be a different underlying issue. Knowing that it was just a software bug, maybe I could have offered to keep it for a decent discount ; TD1 was voided either way, so no coming back from that on future sales.

I got info from the tuner while tracking down the issue; car was flashed on 04/24/2021 with the file "Audi RS5 NA MY2019 2.9TFSI DECA 8W0907551B S0003 Stage 1 V1.3 93 Octane"

[Helios_RS5]

I had a similar issue with similar response from dealer. Twice in October, when I started the car it would immediately shut off with that Drivetrain Malfunction message. I was able to just start the car and drive with no issue. When I took it to the dealer they told me that the control modules were not communicating with each other, probably because of the tune. It hasn't been an issue since, but it's another reason for me to switch to 034 now.

[TSpoolin]

Interesting thread. I recently had an oil filter housing leak that was replaced under warranty. Dealer flagged me TD1 (removed tune prior to dealer visit), but did the fix under warranty (of course tune had nothing to do with oil filter housing leak). After getting car back, I got on it after several miles and blew the coupling off at the exit of the intercooler (dealer had not properly tightened it). I got the drive system malfunction and the car, of course, had no boost. I properly tightened the coupling and initially everything was good for a bit, then I popped the same warning and was only able to generate a pound or two of boost. The warning goes away after stopping and restarting, but comes back as soon as I try utilize boost. I had the APR tune, that I removed prior to visit to dealer. I never encountered this issue when the APR tune was on the car. Took car back to dealer to allow them to check for any other boost leaks. They claim there are no leaks in the piping now, but I still have the issue. Scan shows the dreaded P0299 low boost fault code. Just seems so coincidental that this occurred after dealer visit and I/C to throttle body charge pipe blowing off at the I/C connection. Going to check wastegate play. Wondering if it could be something like bad diverter valve(s)/waste gate(s)/boost pressure sensor, etc, or did the turbos overspeed when charge pipe blew off, damaging them. I do not have any smoke or whining noises from the turbos. I did re-install the APR flash this morning to see if that would fix the problem - no luck, so not the ECU. Will keep everyone informed to my findings.

[wwhan]

Just to complicate things, a few of the early 2019 RS5s had this problem; DTC P25B400 Turbocharger Wastegate A Stuck Closed

https://static.nhtsa.gov/odi/tsbs/20...65545-0001.pdf

[TWRBO]

I never got a CEL or code in memory, but I almost wish I did then so it would have been easier to diagnose. IIRC my car was made in December 2018 so it's possible it would be under that TSB but never popped as far as I could tell.

@Helios_RS5, that kind of makes sense based on the two events I had that caused the issue since both situations were where the trans would have been under high-stress engine braking/downshifting. It's hard to be sure with the diagnosis from the dealers though, never really feels like you're getting all the information

Funny follow-up but I saw my car pop up for sale a few weeks about for about $4k more than I had paid for it. Looks like it was auctioned off to a Honda dealer on the other side of the state. I was pretty surprised to see that pop up in my saved search alerts.

[VVG]

What are people's thoughts on the piggy back computers from either ABT or MTM to avoid just these types of issues? These are just so good now.

[Lethalsouls]

What are people's thoughts on the piggy back computers from either ABT or MTM to avoid just these types of issues? These are just so good now.

There is a long thread on racechip in this forum. It works well, easy to install and remove. That said, I just leave it on. I've had year one and two service done without the dealer saying a word about it.

[TSpoolin]

Turns out my issue was a vacuum line going to the passenger side turbo wastegate. Apparently my dealer did not properly connect back up (along with not propetly connecting my charge pipe connection from I/C to throttle body) when installng new oil filter housing. Such BS, as I took the car back, and they could not locate the issue that my preferred indy mechanic found. They suggested I needed new turbos, knowing I was flagged TD1 - bastards. I plan taking documented work back to them and asking them to cover my costs to get the work done/completed (that they did not do) by a competent mechanic.

[IamRacer X]

Turns out my issue was a vacuum line going to the passenger side turbo wastegate. Apparently my dealer did not properly connect back up (along with not propetly connecting my charge pipe connection from I/C to throttle body) when installng new oil filter housing. Such BS, as I took the car back, and they could not locate the issue that my preferred indy mechanic found. They suggested I needed new turbos, knowing I was flagged TD1 - bastards. I plan taking documented work back to them and asking them to cover my costs to get the work done/completed (that they did not do) by a competent mechanic.

It amazes me how inept some dealerships service departments are. To be honest I have not been extremely happy with either of the two most local Audi service dept. Glad you had someone to give it to you straight. If you dont mind sharing with me, what indy mechanic are you using as we are both local.

[TSpoolin]

It amazes me how inept some dealerships service departments are. To be honest I have not been extremely happy with either of the two most local Audi service dept. Glad you had someone to give it to you straight. If you dont mind sharing with me, what indy mechanic are you using as we are both local.

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