Should it stay or should it go (Audi A3)


KNOCK ON WOOD, but my GTI has been pretty reliable aside from little wear and tear items. I’ve never heard of that code though.


knocks on wood

Yeah, the indi shop basically called me this morning to tell me that they had absolutely zero indication as to what the cause was, and that it would be smart to take it to Audi. No charge for diagnostic. For simple stuff like SMOG, etc, they’ll still get my business. Great guys, super trustworthy.

Which, I guess is interesting as to what it could be. They had no clue. Curious to see what Audi says. Audi will diagnose it for about $100, and will provide a free loaner. If I can swing it i’ll see if they can cover under PZEV and will make a stink to AoA if I have too.

At this point , after 3 water pumps, a fuse panel issue, chucking coil packs on the regular, carbon coking that caused misfires at 60k, a phantom misfire last month that resolved itself, misc interior issues, nav screen issues, and now this… i’m pretty FUCKING OVER THE CAR. It’s bone stock and very well taken care of.

Best case, it gets covered and repaired free.
Ok case, it’s something minor and sub $500 (lol yeah right)
Worst case, I hard park it at Carmax or light it on fire and lick my wounds.

Should we talk again about what I should consider next? Used '15 STI’s with sub 30k miles are dipping into 27k territory, lol


It’s funny how stuff like this eats away at a cars charm when all you want to do is get home.


Audi is quoting me 1300+ to replace the thermostat unit. Brutal.

Any thoughts here? I have yet to call back.


So, more research on PZEV shows that this probably won’t be covered. The verbiage I got from audi was

“we need to start by replacing the thermostat” then test drive the car to ensure no further damage was caused. IT sounds to me, without calling them back, that they are taking a stab at this and going with what they ‘think’ is the cause, first.

I’m wondering if ANYONE here has any insight. Idea’s. Thoughts.


$1300 for a thermostat? Fuck me.


To replace the thermostat you have to pull the intake and the water pump since VAG in their infinite German wisdom decided to bury the thermostat under the water pump and bury that under the intake. At dealer rates it gets to $1300 in a hurry.


Fucking A.

EDIT #2:

Piss. I forgot you’re FSI, not TSI.

So this must be the bit thats failing. But I dont see where its “powered”.



Neither do I. I am all crossed up on this one. I’ll need to better wrap my head around this after work. FML


Is this true? The only video I could find so far was for an FSI motor (mine is TSI) and it simply requires removal of serpentine belt, tensioner, alternator, and then you can access.

This is really tripping me out.


His 2011 is an FSI not a TSI? I was pretty sure his 2011 A3 had the same 2.0 TSI my 2012 VW CC has.


Yea. dont you have FSI??? lol


Ok, he said TSI so I’m going to go on the assumption he’s right and it’s the same engine in my car, which I just had the water pump replaced a few weeks ago on. The PDF “Is it FSI or TSI” guide from ECS Tuning also says his car should be a 2.0 TSI so I’m 99% sure it is.

Then if it is a 2.0 TSI, yes, the intake and pump have to come out to get to the thermostat.


I wish we had vcds codes here and not OBD2 ones. It might make more sense. Im trying to fig out what sensor or whatever “Heater Control Circuit High” is referring to.

In either case I dont see any thermostatic heater on the normal tstats. They are just in different housings on TSI and FSI.

There are some VW/Audi with wax motor controlled tstats, but I dont see that on either TSI or FSI.

Which would look something like this:



Mine is TSI. What a nightmare.


This is fresh in your mind so i’ll assume you are correct. I hope they replaced your TSTAT while in there.

I am struggling to justify repairing this, or paying to repair it if it’s this big of a job, and potentially not the root cause.

My gut tells me to tow it right next to a carmax and fucking get away from it. or light it on fire. or drive it off a cliff. or drive into oncoming traffic.



Ok, so its TSI.

But again, what is failing high… thats what I dont get. Im guessing you just have a generic scanner and not vcds.


A quote from VW Vortex:

TSI engines have that external water pump that is driven by the front balance shaft. So it’s over by the starter area. Similar to the FSI, the TSI has the thermostat encased in that plastic housing…BUT the TSI also has the water pump in that same housing and is driven by a little cog belt. It too is sorta a PITA.

As for the FSI guys…if you are tackling the thermostat, I would recommend a little more routine maint. and just take the intake off. While you are there, clean and reseal the injectors and clean the valves. It will make your car idle smother and have a smoother powerband without the buildup on the valves. It also makes the thermostat 80% easier to do and no alt. removal needed. I work on these cars every day and can personally take the intake off and replace the thermostat quicker than most people can do it just by removing the alt./boost pipe. It’s a few more $$ for the intake gasket, cleaner and injector seals…but why not do it all at once?
-J. Hines

Still digging around on this. Keep it coming guys.

I potentially have long term use of a 2010 Hyundai Elantra that could buy me the time to tackle this on my own. Despite how I may come across on the boards (lol) I’m fairly capable and could tackle this myself. Hell, having the intake off could give me a good look at where the intake valves stand at 112k. Last cleaning was almost 60k miles ago.

My only problem is paralysis by analysis.

@juicedz4, correct, no VCDS currently. If Audi is saying Thermostat, i’ll see if I can better understand what codes they are pulling with VAG


I’ve noticed that some people experience the exact OPPOSITE symptoms with theirs where it may take longer to warm up or never hit normal operating temp, indicative of stuck OPEN, not closed.

and of course, of everything i’ve read so far, no one has shown a code for P0599. Truly puzzling.


Yea, the P0599 is throwing me for a huge loop here. So you must have a map controlled thermostat but NONE of the replacement parts i see for a 2011 A3 TSI show it!!