Possible Tcm issuse ?

[Matt360x]

Hi guys. I have a 2008 a4 Quattro and for the second morning in a row I go out to and start my car the PRNDS is not lit. When I put it in reverse it grabs the gear hard. When I put it in drive it won't shift. Even with paddles in manual shift. But when I turn car off and back all is normal. Really stumped scammed car and it's saying "loss communication with tcm " the three codes that I have throw are
00955(key1 lost)
01315 ( no communication Tcm)(passive/sporadic)
49409 (no communication Tcm)(passive/sporadic)

[Operator]

I would check all the connections/wiring going to the TCM from the ECU. Since the issue is intermittent, it could be something is loose. Worse case your TCM is going out. If that is the case, you are better off, getting a used/transmission, vs going to the dealer for a TCM swap.

[Matt360x]

Thanks for advise. I will be looking for loose wires bad connections ect. But is the Tcm in the transmission or under ecu on the b7's thanks again.

[Operator]

Thanks for advise. I will be looking for loose wires bad connections ect. But is the Tcm in the transmission or under ecu on the b7's thanks again.

The TCM is in the transmission, and is not an easy swap. Dealer wanted to charge me $2700 for a new TCM. I bought a used transmission for about $450 (since a "new" TCM would be inside) and just swapped the trans. Though we are getting ahead of ourselves, and you may have a simple fix on your hands.....

[Matt360x]

So I checked out the main connector to my transmission. The pins connector and wires all looked in great shape. No corrosion or splits i

[Matt360x]

In wires. Do you guys think my printed circuit board under shifter may have something to do with it ?

[Matt360x]

So I managed to have my scanner plugged in while the transmission was acting up. The scanner could not see trans at all. It wasnt communicating at all. I've cleaned and checked most of my grounds. Checked trans wires all seems fine. I don't understand how it could not shift and then as soon as I cycle key after driving it down my driveway it's fine. And it only acts up after it's been sitting for a long period of time. Any one have any ideas at what it could be? Before I start looking to replace Tcm

[Operator]

My issue ended up being a loose CB, which kept losing communication between the TCM and ECU. But my problem was my car wouldn't even start.

[mtroxel]

I'd tell you to get a diagram (I could PM you one) and do a continuity check on all wiring in and out of the TCM. But I think that's a fools errand since it seems the TCM runs fine once it's booted up. If there was a wiring problem you would think it would drop out while you're driving/vibrating.

In another part of my life I diagnose bad computer hardware. And the first thing I'd do with those symptoms is check for bad capacitors on the pc board. I understand that's not simple to get to at all. But when hardware acts strange, that is a very likely scenario. But think of this as a computer that's not booting up. If it's getting power, then the problem is in the computer hardware. And I have a hard time believing wiring is the issue when it runs fine after a re-boot.

[Matt360x]

If you could email me the diagram that would be great. I would like to measure out when it's cold and again after its warm so I know for sure before I change Tcm. Does any one a good place that will rebuild mine. I also have been trying to look for what the input voltage is going to trans.

[Matt360x]

My email is [email protected]

[Operator]

If you could email me the diagram that would be great. I would like to measure out when it's cold and again after its warm so I know for sure before I change Tcm. Does any one a good place that will rebuild mine. I also have been trying to look for what the input voltage is going to trans.

If you think it is your TCM, you are better off just swapping your Trans. Heck if you were local, you could have my old one for cheap..... You will find sourcing a TCM alone is not easy. And swapping one will be as trying. The easy route is to just swap the whole trans if you truly think the TCM is bad.

[Matt360x]

The harder I look the more it points to my Tcm. I found a few used trans for around 600-700$

[Matt360x]

And I can't find a Tcm anywhere haven't called dealer yet but I could only imagine the cost. It's very disappointing to me. My car only has 70k and I have to do a major repair. Only onther thing I could think of is the printed circuit board under my shifter.

[mtroxel]

I just emailed you....so edit that post and remove your email addy.

[Matt360x]

Operator did you have to code your new transmission or was it a direct swap. Called dealer today and the new metracronic system is 1900$. They do not sell just the Tcm. I talked to a local European shop and he mentioned checking my can bus. I did pin out connector on trans. I have 12 volts on pin 10,14,11,9,3 ground on 13,16. 5volts on 1,4,5 and 2.5volts on 2,6. I found a used trans for 500$ with 6 month warranty. At this point I feel that is my best option. Thanks for the help guys.

[Operator]

That's what I've been saying. If your TCM is bad, your best option is to just swap in a new to your car transmission. As for coding, I didn't swap it myself. But as long as the trans code (for me HYH) matches it should be a direct swap.

[Matt360x]

So I dropped the car off at a local garage for a professional opinion and it is indeed the Tcm. So I'm going to go with a used tranny with same code (hyh). Does anyone know if it needs to be coded. When I called dealer for a new Tcm they said it was part of the metrotronic unit(1900$) and was vin specific and made to match my vin/ecu. As operator has stated its a direct swap. If it's a direct swap I'll do it myself. Has anyone done one and can confirm this ? Every shop / dealer I talk to I get different answers.

[Operator]

In my situation I simply ordered a new (to my car) trans. had it installed. Nothing to my knowledge was vin specific, accept for my trans code (HYH). Even if the dealer has to code it, just get the car towed there, and they can charge an hour of labor to hook up, and recode it. But I don't know if that's required.

[Matt360x]

So I put in a new valve body from a used tranny same code and works fine. So it was my Tcm if anyone ever runs into same issues as me. (Hopefully not ) thanks for the advice operator

[nachofly]

noob question here, where is the TCM located?, you said it was a TCM problem, the you said you replaced the valve body, is the TCM located on the valve body?.

Cheers

[Matt360x]

Yes it is attached to the valve body and part of the metrottronic unit.