drjonez

I've visually inspected, I don't think there's anything wrong with the trans itself....I just wasn't willing to go to all that work and not replace it. Based on VCDS, logs and experience, the TCC was the issue.

jzw

Found this thread when i am doing research on my transmission issue. A couple of questions. First, is a VCDS system necessary to see all the information on a vw or audi car? My mechanic has two pretty big scan tools that are almost the size of an ipad. He told me these were the most commonly used scan tools by professionals. Is it possible his scan tools missed some information? Second, the transmission issue i experienced happened to me all the time but not when i test drove the car with my mechanic. So if any fault code was thrown during my drive, should it be stored by the car's system and be available later for scanners to find? I think it should. But my mechanic didn't find any code. Does that mean no code was thrown when the transmission had the issue?

drjonez

It really depends on what scan tool they are using. That said, VAG vehicles can have a myriad of issues that will not throw a CEL or show up on a normal scan tool.

jzw

So is it worth buying it a vcds system? i saw on ross-tech's website, a 3 vin system is $199. It's not too bad. I intend to get another q7 anyway. So it might come in handy in the future.

drjonez

If you're going to continue to own a VAG vehicle and you don't want to pay dealership price for repair, VCDS is near mandatory.

jzw

Did some research today. It seems a VCDS system has a lot of PRO features. All i need is to have a scan tool with me so that i can use it when driving in my town. Note that somehow i just couldn't reproduce the issue when i was at my mechanic's. But it happens to me all the time when i am in my town. So question is if a cheaper system like odbeleven or carista is good enough to capture the potential fault codes thrown by the transmission or only a vcds system can capture vw or audi codes?

-Wes-

Having a Bluedriver and VCDS, I'm going to say that there are a metric crap-ton of codes that the VCDS can pick up that the Bluedriver cannot. However, If I'm just wanting to turn the CEL off or pulling to see if the reason it turned on is the same as the last time, then the Bluedriver works fine in a pinch.

Personally, I think the VCDS is an astoundingly good value for the amount of times I've used it (and for all sorts of things, such as coding new fuel injectors when I replaced those earlier this year). I recommend a VCDS for anyone that has even a scrap of DIY in them.

What I like about a system like the others you mention is that they are highly portable, so I can use them equally well across any newer vehicle I own.

Pothole5000

My fried who was an Audi tech for 7 years said they had 2 OEM scan tools in the dealership, and 10 laptops with VCDS. That tell you everything you need to know.

VCDS simply cannot be beat if you want to work on any VAG car. VAG have been running CAN networks in their cars for years and all the other brands are now slowly catching up, but speak a different language. The generic scan tools are good if you work on multiple brands but cannot get into all the modules that VCDS can as its basically the same as the OEM scan tool.

drjonez

The saga continues....towing season started this past weekend and I experienced the TCC drop out within 15 min of the trip. I did a rolling restart of and carried on. On a whim, I slapped it in S mode and noted better EGTs and coolant temp due to the higher RPMs. I towed the rest of the trip in S and used cruise sparingly on flats or downhill without issue.

I did install a Oakes Performance stage 1 TCU tune back in November. It doesn't seem to make much of a difference for towing.

Current thoughts:

• All last year I towed in D and used cruise. I need to go back through my logs and see the freeze frame data, but offhand I recall it dropping out frequently on uphills. Cruise likes to lug the engine and perhaps the TCC doesn't like that (certainly worst case)
• Towing in S seems to be much better all around- lower temps as noted above and lower trans temp as well. Granted, there's a hit to fuel economy depending on speed.

I'll continue to update this as I suffer.

'10Q7TDI_Prestige'

FWIW, in everyday driving I use my cruise control a ton (to keep me within local speed limits) combined with Sport mode on tranny, as engaging the cruise control when in Sport mode instantly allows the tranny to go ahead and take the next gear rather than maintaining those 'sporty revs' levels. This also allows for greater engine braking while tranny is in Sport mode and as noted above, reduces the strain from carrying too high of a gear, and reduced effort/load equals reduced heat, etc., etc.

I've also noticed in our 4L Q7s and several of the 4M chassis loaner cars I've had that the cruise control can drop out from random 'triggers', such as a particular sensor or feedback loop, such as the traction control system getting confused when going over train tracks or broken pavement, etc. On the 4M cars specifically, it was generally the lane-keeping/lane-following systems that killed the cruise control due to rain or hitting an uneven patch of roadway (traction control system again) that aborted the cruise control, etc. With the 8spd tranny (7 & 8 are dedicated 'overdrive' gears for highway speeds), so if/when towing anything heavy I wouldn't want to be using the top overdrive gear anyhow, IMHO. With the 6spd tranny on the earlier Q7s, those run higher revs at highway speeds, so Sport mode and cruise control is a perfect match-up, but on either the 6spd or 8spd tranny you've still got the 'manumatic' shift function in case you want a different gear that what it's providing you, and the cruise works with that input option too.

Happy towing!!!