Stranded(ish) with P2181 cooling system performance DTC.

[GoCougs1234]

Sounds like a romcom but not really. I need to be home for Xmas like any normal person.

1,500 miles from home when I get the above DTC. Engine fans run full turbo all the time. No tools of note save for an OBD-II scanner. Of course most everything is booked out or understaffed due to the end of the week + impending holiday - whether it's the dealership or trucking services.

I let it sit over night and the problem persists. Vehicle seems to drive as normal otherwise, including normal oil temps and working heat and AC. I did hear a periodic whistle but was unrelated to turbo spool, engine RPM or vehicle speed. Never tracked it down as it disappeared after I was able to get off the freeway.

Also, I get only the above DTC - no CEL about excess engine temp or the like.

There's A LOT of info on this DTC for Audi vehicles but not exactly an answer to this question. To me, it seems whatever has gone wrong the result is excessively cooling the engine; not good but way worse than not enough cooling, and maybe speaks to being able to get home (drive time = ~11 hrs/day x 2 days).

To what extent is it risky to drive ~1,500 miles home? Stupid question maybe!

[SQ5onFIRE]

Sounds like a romcom but not really. I need to be home for Xmas like any normal person.

1,500 miles from home when I get the above DTC. Engine fans run full turbo all the time. No tools of note save for an OBD-II scanner. Of course most everything is booked out or understaffed due to the end of the week + impending holiday - whether it's the dealership or trucking services.

I let it sit over night and the problem persists. Vehicle seems to drive as normal otherwise, including normal oil temps and working heat and AC. I did hear a periodic whistle but was unrelated to turbo spool, engine RPM or vehicle speed. Never tracked it down as it disappeared after I was able to get off the freeway.

Also, I get only the above DTC - no CEL about excess engine temp or the like.

There's A LOT of info on this DTC for Audi vehicles but not exactly an answer to this question. To me, it seems whatever has gone wrong the result is excessively cooling the engine; not good but way worse than not enough cooling, and maybe speaks to being able to get home (drive time = ~11 hrs/day x 2 days).

To what extent is it risky to drive ~1,500 miles home? Stupid question maybe!

Your ran is running constant? Check your coolant level if that’s good and your temps are not over heating you should be fine. The likely culprit is either a bad temperature sensor itself sending incorrect signals to the ecu, causing the fan to run continuously as it thinks the engine is overheating. Or a failing thermostat. Either way if your temps look good other then maybe I wouldn’t want my fans constantly running for 1500 miles you should be fine.

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Fan

[GoCougs1234]

Thanks for the info/advice.

I found a local tuner shop but it didn't work out - they had it almost two days and never touched it despite promises to the contrary - a walk-in just before a big holiday was risky - still disappointed though. I'm OTD to go rescue it. I've called other tuner shops - either telling me I need a new engine (yes, really, without even looking at it) or simply saying they'll call back, but don't.

Additional info is as I dropped it off at said tuner shop, there was an intermittent whistling noise coming from under hood, and it was independent of engine RPM, turbo spool or vehicle speed. Sure sounded like a vacuum leak. By the time I got off the freeway it was gone. However, as I popped the hood the oil fill cap looked oily. Wasn't sure if it was my imagination now knowing the 3.0T has pervasive PCV problems. All still drove fine and looked normal (oil temp) however (and no actual oil leaks or milkshake residue on the underside of the cap).

[BlueB9SQ5]

I had the same issue on my 2020, on my way to thanksgiving last year. Fans went full blast and it was maybe 40 degrees at most. it was an alarming sound I never heard before. Shutting the engine on/off didn't make them turn off. Fortunately I had my scanner with me, DTC P2181 and P1BB4. No check engine light. I reset the codes and it continued to be "normal" after that for a month. But only driving short trips and not knowing what normal oil temp was, it would only reach about 150ish when just driving casually in the cold weather. During a 3 hour drive on the highway I noticed 157 degrees of oil temp was as high as it would go without getting into boost and it cooling back down again. Car just hit 40k miles and I only had it a few months so I was perplexed. Over the next few weeks paying attention to temps, the coolant temp starting having days that I'd only get 3 bars instead of the normal 4. I took it to a dealer, knowing I'm TD1 with the TSB 19 22 29 2058767/8 in hand, thinking I'd be covered. Dealer denied warranty coverage, turned out to be the thermostat. As long as your coolant temps are good, and the oil temp is not really cold, driving it should be ok to get you to Xmas and back. Don't bother going to the dealer, they will rape you for a thermostat. Service mode does take some effort and time, but their rates are ridiculous. Sounds like the thermostat is failing, but just hung open for that moment. As long as the fans are not running WOT, I'd run it. Deal with it when you can. Good luck!

[SQ5onFIRE]

I think you need to find more reputable shops if their answer is new engine or no reply. Like I said I think this is something easy you can do your self if the boxes above are checked. It’s a new temp sensor, thermostat, or even worst unlikely case a poorly running coolant pump. If temps are good it’s unlikely the later.

[GoCougs1234]

If I didn't have to be home for Xmas I'm sure I could find a good shop here given time. I have a good shop at home.

The fans are indeed running WOT, like full MFing turbo - like I've never heard, even after extended hard driving in mountain passes at like 95F.

I picked it up from the shop. All they did was an OBD-II scan and got the same codes. They said their fix-it database said 80% chance thermostat, 15% water pump and 5% misc. Since all drives and works fine save that the fans are on full MFing turbo, I look to be in the 80%.

Even when allowed to sit over night (it's getting down to ~40F here), upon bone cold start the fans immediately go MFing turbo, so it's in some sort of failsafe mode. But no CEL or dashboard warnings - only DTC via OBD-II scan and fans running full MFing turbo. As such, the shop said if they were in my shoes they'd chance it and drive the 1,500 miles home. Push come to shove I'll get dashboard warnings and CELs if things go bad (and I have towing insurance).

[GoCougs1234]

So the the morning of the first leg of my trip back home I reset the DTCs and upon startup all was solved - no more fan funny business for the ~1500 miles back (and TBF and fair amount of hard driving). However, halfway through my trip, upon startup in the morning, I got a bunch of dash warnings, a few of the "do not drive" variety (sport diff, dynamic steering) - and FWIW it was legit as I had ZERO steering assist. Restart solved all and they've not been back. I forgot to mention in the original post that just a few days before the cooling system SNAFU, I started getting noticeable turbo whine that seems to have gotten louder. Jesus, bunches of things pretty much all happened out once. They seem unrelated but coincidences rarely are. Tomorrow, I'm having my tuner shop investigate all to the best of their ability:

1. Cooling system DTC and fans on full MFing turbo (solve with clearing DTCs + cold start)
2. Prominent turbo whine (still present)
3. Intermittent whistling of the vacuum leak kind (now gone)
4. One-time dire dash warning onslaught (solved with a restart)

[Txlifter]

How long have you had your tune? Sounds like you might have lost your compression side, and other things are working overtime trying to keep up. Good you made it home though, Merry Christmas!

[GoCougs1234]

How long have you had your tune? Sounds like you might have lost your compression side, and other things are working overtime trying to keep up. Good you made it home though, Merry Christmas!

Currently at 89k miles. Stage 1 from 36k to 75k miles and stage 3 from 75k miles on.

Just got back from my tuner shop. They put ~2.5 hours into diag and NPF on issues 1-3 (they didn't investigate 4). The turbo was the most concerning to me but bearings were tight and testing passed for both leaks and mechanical operation (solenoid, waste gate operation). They took video of the turbo whine and will report to APR - will hold for now on next steps, if any. They saw evidence that the PCV is on its way out (oil seeping out from under the oil fill cap). So, after the verdict comes through for the turbo and then onto preventative maintenance. In the meantime, I can easily handle the PCV parts replacement.

[SQ5onFIRE]

Currently at 89k miles. Stage 1 from 36k to 75k miles and stage 3 from 75k miles on.

Just got back from my tuner shop. They put ~2.5 hours into diag and NPF on issues 1-3 (they didn't investigate 4). The turbo was the most concerning to me but bearings were tight and testing passed for both leaks and mechanical operation (solenoid, waste gate operation). They took video of the turbo whine and will report to APR - will hold for now on next steps, if any. They saw evidence that the PCV is on its way out (oil seeping out from under the oil fill cap). So, after the verdict comes through for the turbo and then onto preventative maintenance. In the meantime, I can easily handle the PCV parts replacement.

Get the 034 pcv replacement. Won’t have anymore issues. I got it works great.

[Branman1]

Did you ever fix this? Same code just popped up for me.

[GoCougs1234]

Did you ever fix this? Same code just popped up for me.

Nope. I scan/reset DTCs once a week and P2181 is always there. The cooling fans stuck on mega turbo speed never returned however. I also can't see/smell/hear/feel any issues. I drive it hard pretty much every day so I'm surprised it hasn't gotten worse. Either way, my tuner shop says it's an indication that I have the inevitable water pump/t-stat repair in my future. Their recommendation was wait till I get dash warnings, CELs or see/smell coolant leakage before proceeding (since it's quite expensive).

[athree20v]

FWIW, my wife's 2019 SQ5 just had this same thing. I noticed dried coolant on the coolant shut off valve on the front of the engine, so I went ahead and ordered one from FCP. While I was in there, I decided to just do everything...waterpump, thermostat, and shut off valve. FCP has a kit that has all the hardware and o-rings for the job. Coolant flush/fill afterwards and the issue is gone.

[ontunerow]

FWIW, my wife's 2019 SQ5 just had this same thing. I noticed dried coolant on the coolant shut off valve on the front of the engine, so I went ahead and ordered one from FCP. While I was in there, I decided to just do everything...waterpump, thermostat, and shut off valve. FCP has a kit that has all the hardware and o-rings for the job. Coolant flush/fill afterwards and the issue is gone.

Do you have a link or FCP product ID for that kit? Gotta feeling I'm around the corner needing to address the same things.

[GoCougs1234]

FWIW, my wife's 2019 SQ5 just had this same thing. I noticed dried coolant on the coolant shut off valve on the front of the engine, so I went ahead and ordered one from FCP. While I was in there, I decided to just do everything...waterpump, thermostat, and shut off valve. FCP has a kit that has all the hardware and o-rings for the job. Coolant flush/fill afterwards and the issue is gone.

What did your coolant leakage look like? Did you have low coolant warnings?

My coolant valve looks just like this (not my pic FWIW) - no smell though:

[athree20v]

What did your coolant leakage look like? Did you have low coolant warnings?

My coolant valve looks just like this (not my pic FWIW) - no smell though:

Shut-off valve had dried pink crusty coolant on it, and the car for the longest time had the faintest smell of coolant, with never any evidence of an active leak. Maybe twice during an oil change, I had to top off the coolant, but never any low coolant warning. Perhaps it really wasn't the shutoff valve, but rather the thermostat that was the problem. Ill never know as i just replaced everything while the front clip was off. Easy job if you can turn a wrench and have a vacuum filler...You can save big money if DIY.