QUIGGS2001

Unfortunately I've recently discovered my 2011 A6 has this very same issue. Coolant leak into the Mechatronic Unit. Unfortunately a new valve and deep clean of the connector pins didn't rectify the issue, and my mechatronic unit is now with ECUTESTING.COM to be reconditioned..

An expensive repair no doubt. The only upside is they give a lifetime warranty on the repair and have a 2-3 day turnaround. I'm in Ireland, they're across the pond in England.

I'll provide an update this week hopefully..

FirstAudi2012

I'm doing my own maintenance now (after the $11k quote) and just completed the 125000k service (oil/brakefluid/transfluid & filter). Checked the main trans connector and still looks good / no more antifreeze ... only the dielectric grease I've applied. Reapplied, reinstalled and the car is still functioning normally.

QUIGGS2001

got my car back two nights ago, I've done around 100 miles since, with no issues.
ECUtesting didn't have to replace any parts of my mechatronic unit, but it did need a cleaning. Due to the fact I took my car off the road immediately the very first time I got the dreaded gearbox malfunction message on the dash, I must have saved any further damage.

So repair of my wiring harnesses, new coolant pump and lots of lovely new gear oil and I'm back on the road a very happy man!

mdskiman521

Yikes! This isn't good. I did find the TSB listed on NHTSA. They list the models and the VIN range.

https://static.nhtsa.gov/odi/tsbs/20...58574-8951.pdf

Since I just replaced pistons and rings I will check this one out.

Mesquite77

mdskiman521, is your PP 2.0L or 3.0L, because some 2.0L from 2013, like mine (PP Quattro ZF 8spd), do not have the offending transmission coolant valve at all, direct connect to transmission cooler. I pulled my tranny connector at 65K to check, and it is perfectly dry and clean.

It may be that for southern states they omitted, since it pretty darn hot here all the time?

mdskiman521

Yes, mine is a 2.0L. Nice if I didn't have to do this one.

I looked up the parts listed in the TSB and one is valid for my car.

Required Parts and Tools
Please reference ETKA using the VIN of the subject vehicle to ensure that the correct valve is being ordered.
Part Number Part Description Quantity
4H0121670A Solenoid valve 1
4H0121671D Solenoid valve 1

Mesquite77

Follow the pipe against the left side fender, from the coolant pump near rear of block, down to floor by front drive axle, then if there is no valve there, it will be just a connector to another pipe that goes to tranny. If the valve is is present, it will be there in place of the connector with a wire harness. BTW, once you pull off back belly pan, it is very easy to pull tranny connector and look as in pics posted here.

mdskiman521

Looks like the 2.0t may not be impacted. I just took a quick look and I found the hose and it looks like it goes underneath the connector someplace. It looks like there is no hose near the connector. There is a tee is farther up the line and another hose connector a few inches or so down the line from where I marked the hose.

Picture below. You can see the hose on the right on the wheel well. This hose goes down below the connector on the left and continues past the the connector back under the axle...

Mesquite77

Yah, that pipe on right goes to tranny cooler, no valve. The TSB is confusing, since like you, my VIN is in the range, but I had both belly pans off of mine, did a DIY replacement of the main coolant pump, and there is no transmission coolant valve.

The 2.0L gets a lower rated tranny then the 3.0L, so maybe it is slightly different with its coolant range spec, or in the production run, they realized the valve problem and just put in a straight pipe and left it out, who knows, but a good thing I think.

Audi-6

So I this just happened to my 12 a6 with 65k. Is this something we can fight? How do automakers decided what to recall/tsb on defective parts/designs?