Anyone ever have a TCM problem on the A6 ? No codes or CEL but trans is acting strange, no downshift with paddles in drive or sport, shows X on hud. From a stop it will start out in 2nd or 3rd. I did do heads/cam and exhaust this winter, have been working with my tuner but still can't get it any better. Maybe a coincidence the TCM went bad when the changes were made ...?

 

TCM is in the bottom of the trans, so no joy getting to it.

As for problem, could be with the tune on the TCM, or could be the TCM/one of the solinoids instead.


So on that note, would double check the TCM connector to make sure you don't have a pin corrosion problem to start with. But short of that, sound like you may have to go into the trans to trouble shoot the TCM/solenoids isntead.

P.S. Mileage would help, since it may just be a clogged trans filter to start with.

 

Just hit 30,000 mi and had the fluid/filter changed last summer at a GM dealership. My tuner tried a previous file from last year too. Going to put it on a lift tomorrow and looking at connectors etc. If TCM was faulty would it throw a code ?

 

Would check the connectors, and just flash back in the stock TCM file through SPS to make sure that the problem is not in the tuned file to begin with.

As for tuner, what software is he using, since you stated file from last year, and almost sounding like a Canned toon file that may be corrupted to start with, instead of going in with HP tuner to change the needed perimeters on the OEM flash instead.

Also, I bring up canned tunes, since even if you do have the oem TCM file saved, it may be corrupted as well, and why I suggest that the TCM is reflash back to stock with GM SPS to start with, to see if the problem is in the TCM/trans, or the after market tune to begin with.

 

A friend of mine owns a trans repair shop so he put his Snap on scanner on it and we drove around. Nothing wrong with the trans itself, no codes, tcm is getting the info but not acting on it. The only way it would start out in 1st is shut it off and restart. I had him order a new GM tcm.
Dano, the saved trans tune was just from the tuner turning up shift pressures last year. HP Tuner

 

Dano, does the new TCM need to be programed by a GM dealer ? Bought a new GM unit and they asked for vin so I assumed it would be married to the car. Car is off the ground and it starts and can shift the trans. Not showing trans temp on dash but the tech 2 shows temp. Waiting to install new tires next week and I'll drive it to see what happens....

 

Considering that there is firmware in TIS2000/TDS to flash the TCM, would say yes on the flash to marry it to the car/get it on the needed security code with the BCM and ECM. Hence half the time, it may just marry it self if the dealer already vin programed it to to start with and was not married, but not a bad ideal to just flash it once in the car.

If you have a tech II, then can just get a $40 subscription to TDS for SPS, and may just need the Ubs to serial port cable to connect the tech II to your computer if you don't have a Rs232 on your machine to use the factory Tech II to computer cable.

A/C delco tds,
https://www.acdelcotds.com/subscriptions

cable if you need it,
https://www.automationdirect.com/adc...bles/usb-rs232
Or

Driver for cable if Win does not download it automatic. Hence I run Tis2000 in a VM shell under XP, so had to down load the needed driver for the shell since it was not part of the XP autodown loads.
http://www.prolific.com.tw/US/ShowPr...0017-0037-0041

As for once you have the TBS subscription and go to use SPS the first time, TBS will walk you through the software and Java software install needed on your machine to use TBS SPS with the Tech II to flash the TCM.

Screen is semi dated for when SPS starts to run, and will have a list of three items that you will need to load on your machine when you get the pop up at the start of SPS.
Attachment 48333893

Again, dated and for a C7, but Your wanting to select TCM and BCM immo learn to flash the TCM and get it on the same security key as the BCM.
Attachment 48343116

P/S, if you where Denver local, would just drop by to flash it for free instead.

 

Useful info there, thanks. I wish you were closer but I might try it myself.

 

Man this thing is killing me. Installed new GM TCM, dealer married it to ECM, downloaded new program and still pretty much same problem ! Going to unplug MAF tomorrow , unplugged alternator, then O2's, no change.......

 

Hello Raffman I’m unfortunately having the exact same problem as described.
My car too is a ‘11 grand sport but sense my LS3 windowed the block went with an LS7

Here’s a quick run down of what I been true;
Out of nowhere the trany started to malfunction
paddle shifter down denied but up will work thought not for 5th or 6th some times at times for 5th but not 6 and simultaneous conflicting actions were taking place like if I got on it hard say at 80% throttle it may out of nowhere go to neutral then engage again it was insecure at best to get on it and it did too start of in second or third and even in fourth some times at the stop light so my tuner in no way could take control of it or tune it as he use to it just won’t do as commanded to like before so we thought the tcm maybe bad I changed it and reprogrammed it with a known good tune we had in it before, it did exactly the same as with the original tcm nothing changed one time on the way home I got on it and then lost going into 4th will just go to neutral I decided to take down the trany and go true it this was a fully build trany by the way no short cuts including billet intermediate shaft with power glide clutch packs upon disassembly I found the planetary broken otherwise the transmission was like new and totally clean inside.

So this engine makes 606 whp I decided to get a billet rear cluster to take out the weak link while in there “BUT” also got me new upper and lower valve bodies and another new tcm to be flashed with a fresh original tune and modify that to eliminate any possible corrupt file, with the trany back together guess what same problems persists still driving the tuner crazy denying down shifting as before and like you I went to a body to check any trouble codes with a expensive powerful Snap-On diagnosis tool there were no dash check engine lights or any complaints just a couple of lost tcm/cluster communication and even/tcm/ecm communication.

So my next step will be to look into why I’m getting check oil level I already changed the oil pan level sensor still not able to read oil level ones I get this fixed my hope is the lack of communication will go away and all be back to normal will find out Monday.

Bellow broken planetary and the one it was replaced with.

 

Yes, similar but mine never went to neutral. I'm retracing all my steps from the heads/cam swap and nothing yet. I talked to another forum member who posted similar problems and his turned out to be taller rear drag tires. I'm about ready to contact a Psychic !

 

A psychic? (I hope you are kitting) the devil only know to do 3 things kill steal and destroy which one of those do you need there’s only those 3 choices and of course he’s going to lie and get you to do something to obey him so he can acuse you before God to obtain permission to get on with his work then you’ll know the science of evil.

I’ll go to my knees and ask for what I need & never get hurt I know this too should pass I’ll have my brake true on the way to my next track day and some sub ten sec passes i’m almost there with a better and stronger transmission than ever before.

You should be ok too these enigma make us wiser and better but do require some finessing.

 

Uhh devil worship aside, I unplugged the MAF went for a drive and trans did what it is supposed to do. Cleaned it, didn't work so picking up a new one tomorrow.

 

Im surprised the engine works without the MAF I’m delighted to know you got it working will certainly be giving it a shot myself as well.

 

Well new AC Delco MAF had no effect. No damaged wires, pins all look good. Can't understand why disconnecting the MAF allows the trans to shift normal !

 

I talk to my tuner he said you likely have a hand held programmer or a can tune in there
He said the way he programed the maf I wouldn’t have that problem he also found the pressure control solenoid d stock open in the valve body.