Installed replacement flashed TCM, car won't start

[AudiAnne]

Hi, would really appreciate some input and advice please. So, some background. In a moment of romantic madness my beloved bought an 2003 A4 B6 Cabriolet.

It is extremely clean, and reasonable mileage for the price. Driving it home he noticed a shudder/hesitation when accelerating, which got progressively worse.

Oh, did I mention we had to replace the oil pan, plugs (they were copper!!!), coil packs and vacuum actuator.

No check engine lights at first, then the shudder got extreme and the PNRD indicator light started flashing.
Searching this forum lead us to the conclusion that the TCM failed - apparently a common fault, and unfortunately we were too old to get the dealer to replace it.

we removed the original TCM and sent it to be repaired, and were informed that it couldn't be repaired as it was the main integrated chip that had failed, but we could purchase a new one from them for $1200....

We didn't have that kind of money, and were very dubious of the people we sent this to so we got ours back from them, and yes, I know, I know, bought one online from China. They flashed it to our VIN number, but when we put it in, the car won't start, it doesn't even see the TCM. It's an automatic, and the dashboard is telling me to push in the clutch to start it!

My questions are , is this because the new component doesn't have the same security code as the car, and if so, how can I change it.

Thank you all in advance!

[old guy]

You can try bypassing the clutch interlock relay and see it that will allow the car to start. Clicky click®

[wranglerazz]

I have the same problem. My car starts juddering out of the blue while cruising and then when it gets really bad it goes into neutral. After a restart it seems to be ok. I also saw the speedometer jumping up and down at the worst. Funny thing is that the car was parked for a couple of months, and after the very first drive it started juddering real bad uphill and the cruise control wouldn't adjust the transmission for hills etc. Figured it was the TCM since the speed sensor is part of the unit as well. Ended up buying a refurbished unit from eBay that was programmed to my car etc. Unfortunately the TCM is a pain in the ass to replace because of the dual exhaust...

Keep us posted about your TCM problems

[AudiAnne]

Taking the old one out and putting the replacement in was a bit fiddly, I agree (Art of British Understatement on display there....).
Can I ask who you bought your TCM from - we got our replacement from eBay also, and like I mentioned, it was flashed to our VIN number apparently, but when we put it in, the ECU can't see it. We contacted the seller, and he didn't seem surprised and said if we could get hold of ODIS software and VAG5054 reader, it would be a 10 minute fix, hence so we figured it might be due to the wonderful Audi security system of coding every part to the VIN and security code, but was curious if anyone else had this problem and how they resolved it.
Currently car is up on blocks still, waiting a resolution.

[wranglerazz]

I bought the TCM from “cmpauto4s” and as I said it’s a friggin pain in the ass to install so I don’t know if it works yet.


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[AudiAnne]

Thanks for the info, I didn't realise you hadn't put yours in yet.
We found this video to be very helpful, excuse me if you have already viewed it. https://youtu.be/KviONp1gjVo Audi A4 CVT transmission TCM Removal Step By Step, posted by Monty's Automotive.
The hardest things we had to deal with were not being able to get the car very high, we are doing the work at home, with no lift. Visibility was very limited, and it took a week to get the kinks out of my neck. I found myself taking photos of the area I was working on but unable to actually see, so that I could check what I was doing.

[AudiAnne]

Thank you, reading up about this says it means you end up starting the car in gear - that can't be good for the transmission. Have you ever done this?

[old guy]

Thank you, reading up about this says it means you end up starting the car in gear - that can't be good for the transmission. Have you ever done this?

If you are referring to bypassing the clutch interlock switch the caution is for being able to crank the engine over with the clutch engaged. Since you have an automatic that shouldn't be an issue. If your ECM thinks you have a manual transmission the starter circuit gets disabled unless the clutch interlock solenoid relay is active. By bypassing the relay you may be able to get your car to start and drivable until you can get the TCM fully sorted out.

[EuroxS4]

Its a CVT those transmission modules are in the end of the trans. Junk transmissions if you ask me I remember changing them every 20k due to temp sensor failure or the bells wearing. Those TCM's are a one shot deal. Once they are programmed to a vehicle thats it. I dont believe the TCM is part of the immobilizer on that particular car. I would return that part if you can get your money back and see if you can purchase a rebuilt unit from BBA Reman. I have done lots of business with them and never had a Issue. It also sounds like the TCM needs to be coded.

[rollerton]

A little confused by some of this. The TCU shouldn't get in the way of the car starting.; there's no Immo involved in any trans management and it doesn't care about the coding in any way I've ever found as far as starting the engine.
If I remember right I started the engine on my step-kids USP A4 when I did the trans swap- WITHOUT the TCU installed at all. As long as the starter interlock relay is grounded it'll turn over; that particular thing is grounded via the shifter being in P or N. Very easy to get under the dash and jump some wires at the relay to find out.
@wranglerazz-- --If it's a CVT different story, and it sounds like yours is. If so...yuck. Sorry...

--->

[AudiAnne]

Was wondering if you had managed to install your replacement TCM yet, and if so, did it solve your issues. Ours didn't! Am currently saving to send our original unit to BBA Reman, who everyone swears by, and see what they have to say.
Wishing you every success!!

[wranglerazz]

Hi, no i have not installed it. I'm still able to drive it, and so far it has a lot of good days. I'm curious though if it will communicate with the rest of the electronics or if it's just another rip-off from Chinesia! Anyways I'm curious to know if you had any luck with the TCM issue?

[wranglerazz]

The transmission just gave up.


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[AudiAnne]

Hi Wranglerazz, sorry to hear that. We figured out the issue, it was a dodgy connector onto the TCM. We did a transmission service at the same time, and over the course of driving, it has gotten smoother and smoother, the shudder has gone. But it's not all sunshine and roses, the speedo works once in a blue moon, and to top it all off the petrol filler flap is locked and I cannot get it to open. Oh, and the roof only works when you use the key in the drivers door, the 'convenience mode'.
Am in the market for a flamethrower.......

[wranglerazz]

I just replaced the TCM in the crappy transmission and guess what!? It works. Not my first Audi with transmission problems. I've had enough and I'm getting rid of this piece of junk. I'm buying a Volvo.
Goodbye Audi.

[hightime80]

I just replaced the TCM in the crappy transmission and guess what!? It works. Not my first Audi with transmission problems. I've had enough and I'm getting rid of this piece of junk. I'm buying a Volvo.
Goodbye Audi.

Peace!