2016 A6 TDI limp mode

Hello everyone I am first time poster but have been around for a while.
Would like to get your input plz.
The car went into a limp mode with check engine light on and glow plug light flashing.
Continued driving since we were far from home but we made it.
The next day the flashing glow plug light was gone, while the check engine light was still on.
But day after the check engine light was gone also..
Now the car does NOT have check engine light or glow plug light on. And drives ok.
The car has 22000 KM with service just done in Edmonton AB.
But the codes are still there.
Codes
P0234
P0236
P0402
Initially it had P0299 and P2279 but they are gone now.
Thanks for any input.

Did it do this during a cold start on a really cold day? If so try to clear the codes again and see if they go away.
My 2012 Passat TDI had similar codes on a really cold start. All went away once cleared.

Yes it was cold about -20C but the limp mode happened about 40 min after the cold start.

Hi, I really don't won't to clear the codes so the dealer has something to go with.

The dealer will likely clear the codes and see if it comes back before doing anything anyways, especially if the CEL is no longer on. If your dealer is nearby bring it to them and see what they say.

Thanks Radman, the trouble is the dealer is 1500Km away and it is the closest one.
I have traded 14 A6 TDI to get this one, maybe I should have kept the 14...had 0 issues with that one.

Thanks anyhow.

Just read about similar issue here, go to post 21:

http://forums.tdiclub.com/showthread.php?p=5488871#post5488871

[FONT=&quot]Interesting, my car was sitting for a long time also.[/FONT]
[FONT=&quot]I did some mods with Carista like turn off start/stop and enable lap timer so I could see boost and oil temp. After the flashing glow plug and check engine light, the boost was stuck at half for the rest of the trip.[/FONT]
[FONT=&quot]Thanks
[/FONT]
[FONT=&quot]
[/FONT]

I have a 2016 Audi A6 as well and had the exact same codes and symptoms a couple of weeks ago. I live in Wyoming and commute to North Dakota for work during the week and we have had temps well below zero with most of the month of February never reaching 0 deg F. The first time it was -22deg F and I had taken my son to school and then was headed to town and saw the flashing glow plug light and had no power. Didn't have my code reader so not sure what codes were active at the time and they didn't stay long enough to be logged in the permanent memory. I drove in limp mode the rest of the way to town and when I got there I shut the car off and then restarted it and all was well and the symptoms didn't return for a couple more weeks. The second time I was on my way back to ND and temps were around -11degF stopped to get fuel, got back on the highway and made it a few miles from town when the car went into limp mode again and this time set the CEL. I had my code reader handy and found the same codes you had. This time stopping and restarting the car only reset the turbo for a few minutes before it went back to limp mode. I also noticed that the boost pressure was stuck at 22.68psi and never moved for the last 2.5hrs of my trip. The temps warmed up later that week and I test drove the car and had no issues and the codes started going away and have not returned. It seems the problem may be cold related but I'm not sure what is causing it and I have the same issue where the closest dealer is 5.5hrs away so I can't just stop in and have them take a look. I only drive my car when I commute back and forth to work so it generally sits for two weeks in an unheated garage then I drive the 6hrs home then maybe to town 30 miles away and then 6 hrs back to ND. I did notice when I opened the hood to see if I could find any air leaks in the intake that my entire engine compartment was covered in snow including the engine, I wondered if I wasn't getting some moisture into the air intake from the powder fine snow that was collecting and freezing on some of the sensors on the intake system causing erroneous readings.

Did your symptoms return or has all been well since the deep freeze has lifted?

No nothing so far, when I was getting the flashing glow plug driving around town, the car was lurching forward like the throttle was getting stuck. But since the weather is warmer the car is fine.
Will know more in 2 weeks. Have an appointment at the dealer and I really hope they will fix it really like the car, thats why I traded the 14 for this one. But if it is like this not sure if I keep it.
Will report after the visit.

I didn’t have any lurching, but I did have some stuttering/misfiring otherwise it ran ok just no power.

Well, got back from the trip to Calgary to see the dealer if they can figure out what is going on with my car.
They have never seen anything like it so they called TQM (which is Audi engineer for Central and Western Canada they said)
After the dealer described the issues and the codes the engineer said this is an intercooler freezing issue which they have seen in Manitoba but not in Western Canada.(Oh by the time I have reached Calgary the codes were gone)
TQM said there is no engineering fix.
So:
Do not idle (I have idled a lot past winter at least 40 min a day)
Drive it in sport mode
Drain the intercooler at every services.
I have asked about insulating the grill, but they said don't do it.
Also I had the dealer put int oil pan heater, which should help me not to idle as much.

Anybody has any input?
I totally disagree with not covering the grill in extremally cold weather.
Any input welcome.
Thanks

Honestly given the drive cycles required to get a good idea of what's going on with newer motors, it's best for consumers to have their own diagnostic tools so they can present some info to the dealer. egr codes are common on these, and the overboost might be from the colder dense are, but it's a brand new car and should be operating properly. Might take a tech hours of driving around and data logging to figure out exactly what's going on with a vehicle, and they're not really paid appropriately for that sort of work in most cases. They're heavily limited by corporate and it's usually an "oh it has this code so lets replace that part, you're allowed 30 minutes of diagnostics" procedure.

VCDS will show you the instance that triggers the code, you can also data log a few measuring blocks to try to replicate the situation and then save/plot that graph to show a technician exactly what's triggering it. Reason they might not have a "fix" is because it isn't epa approved.

I'd start with figuring out what's causing the errors and present it to the dealer https://store.ross-tech.com/shop/cat/VCDS

Keep in mind, just like going into a doctor with your online diagnostic from webmd, dealerships can be a little dismissive. If you come across competent and have the data to back it up they should be understanding and willing to look into it.

As long as you're keeping coolant under 100c (can check with diag tools, the gauge isn't always accurate) there shouldn't be concerns blocking off some of the incoming rad air that's just killing your efficiency and slowing down warm up.

None of my codes/symptoms have returned either so I suspect the issues may have been due to the extreme cold we experienced this winter since the issues went away as soon as the temps warmed up. Just not sure what the failure mechanism was. I also had some excessive idling and the first time I had the symptoms show up was after taking my son to school and I stopped back at the house to grab some things before heading to town and left my car running and ended up getting sidetracked and didn't leave for a couple of hours. Otherwise before heading out on my long trips it would idle for 20-30 minutes as I was loading up the car and getting ready to head out. I will try to keep this to a minimum and see if the issues return.

I did log some data from one of my limp mode events but my diagnostics software sucked and the data wasn't very useful. I recently purchased a VCDS cable so I will be prepared for the next time.

[FONT=&quot]So, it has been over 2 months since the car went crazy and through a code galore, weather has been warmer, and car is behaving.[/FONT]
[FONT=&quot]So, it looks like the head tech was right about intercooler freezing.[/FONT]
[FONT=&quot]All the issues I had, were from late December till February. Also, this is happening on the 2 L TDI CR and the Dodge EcoDiesel’s. The solution from FCA is winter front. [/FONT]
[FONT=&quot]Coming back from Calgary the car drove fantastically with awesome fuel economy.[/FONT]
[FONT=&quot]Really itching to tune it, would like to get a custom tune which hopefully would increase the life of EGR and DPF (dynamic EGR and more complete burn which should reduce soot). Don't really want to remove the emissions stuff.[/FONT]
[FONT=&quot]Some pics of the mileage 5.6L/100km (42MPG)and DPF regen after 1000km.
[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]https://ibb.co/JBs4DMt[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]https://ibb.co/87fjNpj[/FONT]
[FONT=&quot]
[/FONT]

ykaudi said:

[FONT=&quot]So, it has been over 2 months since the car went crazy and through a code galore, weather has been warmer, and car is behaving.[/FONT]
[FONT=&quot]So, it looks like the head tech was right about intercooler freezing.[/FONT]
[FONT=&quot]All the issues I had, were from late December till February. Also, this is happening on the 2 L TDI CR and the Dodge EcoDiesel’s. The solution from FCA is winter front. [/FONT]
[FONT=&quot]Coming back from Calgary the car drove fantastically with awesome fuel economy.[/FONT]
[FONT=&quot]Really itching to tune it, would like to get a custom tune which hopefully would increase the life of EGR and DPF (dynamic EGR and more complete burn which should reduce soot). Don't really want to remove the emissions stuff.[/FONT]
[FONT=&quot]Some pics of the mileage 5.6L/100km (42MPG)and DPF regen after 1000km.
[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]https://ibb.co/JBs4DMt[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]https://ibb.co/87fjNpj[/FONT]
[FONT=&quot]
[/FONT]

Click to expand...

Which APP/Vag Com unit are you using?

The name is VAG DPF and it is free download on Play store (Android)
There is free version then there is one for $5 with more info.

I use Carista for the ODB2 connection.