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Transmission Issues in 2021

10326 Views 66 Replies 15 Participants Last post by  gkardr6
Title: Transmission Issues in 2021

Hey all,

I've been experiencing transmission issues similar to those that others have had in the past, and am hoping for some help to understand how to diagnose and fix these problems. I've had the same issue three times in a month now:
  1. I drive the car for a while with no issues (the first time I had been driving the car for about 3 hours, the second time I had only driven it for about 30 minutes)
  2. Park the car and turn it off for a little bit (the first time this was only a few minutes as I filled up for gas. The second time the car was off for ~2 hours)
  3. When I go to restart the car I get the "Christmas Tree of death", reverse and manual mode are not available, and only 2nd, 4th, and 6th gears work. The first time this happened the car actually got stuck in reverse for a bit before it finally went into neutral, but then couldn't go back to reverse or into 1st/3rd/5th.
  4. No amount of key on/key off/reboots changes anything. If I pull the negative battery terminal AND let the car sit about 30 minutes, it will suddenly fire up just fine. All the warning lights go off except the CEL, all gears and modes are available, and the car shifts just fine. After driving for some amount of time, the CEL also clears itself.
  5. The third incident occurred while driving this morning. On the freeway with the cruise control engaged and car in auto mode, the transmission light briefly flashes, CEL illuminates, I get a bunch of warnings, but the car continues to shift fine in auto mode. Once I parked and turned it off, it now has all the same problems as in #3 when I try to restart it.
After the first occurrence, I took the car to the dealer and they could find nothing wrong. They double-checked the software was up-to-date (I even provided the number of the SW patch below) and confirmed there was nothing available. They then quoted me $9,000 to replace the transmission, so I took the car back and decided I would have to solve this myself.

To start, I've read all of these threads:

Transmission Failure
Transmission Failure Poll
Heads Up On a TRny Issue
Inconsistent Problems: “The Christmas Tree of Death”.

The problem is that the majority of the problems people had occurred early on, and dealers either solved the problem with a software patch which predates the build date of my car (I have a 2016) or they replaced the transmission. My car is out of warranty so a trans replacement "just in case" is not in the cards.

From what I can gather, these are the possible sources of the problem. Is this list complete and in which order should I troubleshoot this?
  • Clean/brush battery terminals and add dielectric grease - already tried this after the first incident, didn't solve the problem
  • New battery - I tested the battery at Autozone, they claim that it's totally fine, not even marginal on startup
  • Get the software patch that worked for others (CFC8TDW.01-00-UF14M080) - I gave this number to the dealer and they claimed everything is up to date
  • Check/refill "Robot mechanism" (shift actuator?) fluid level
  • Replace shift actuator pressure sensors with this part: Pressure sensor - Alfa Romeo TCT - SequParts
  • Replace voltage regulator for shift actuator
  • Replace hydraulic actuator p/n #68303710AA
  • Replace transmission
Also, is anyone aware of an Alfa tech or indie shop somewhere in the US who actually has experience troubleshooting and solving these issues? The tech at the local dealer had seen this problem many times on Fiat 500Ls, but said that they just R&R the transmission every time, so he didn't have any idea how to diagnose the root cause.

Any help would be appreciated, I don't feel like I can trust my new car enough to drive it anywhere until this gets sorted out.
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Have you asked for a transmission recalibration? Something about adjusting the kiss points of the clutches. My tech gave one to mine last year, I thought as a preventative measure, because I really couldn’t detect anything wrong with it. It did smooth out the changes in certain circumstances. These things are too clever for their own good, and ours.
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How many miles do you have on your 4C, and have you ever tracked it? I'm at 12K on my 2016 so far zero issues but planning to have bolt tightening and other service performed soon in Atlanta. Will definitely be asking about the DCT.
33,000km (about 21,000miles) and tracked 5 or 6 times, Luddenham was a bit of a go kart track. Fun but slow.
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Almost forgot that I took screenshots of the OBD codes I could read with my cheap Bluetooth OBD adapter. This is from the first time I had the issue (although it is after I pulled the neg battery cable):

And this is after this weekend's issue (again, post-reset):

It was suggested to me offline that I buy the Foxwell code reader to grab and reset anything that maybe isn't showing up with my cheap adapter. I have one on order (they are on sale on the Foxwell site right now, btw) and will post any additional codes that I can see once I have it. A quick Google on the codes above shows some possible issues related to the gear position sensor, so I may add that to the list of possible trouble areas.
If you have the e-manual you’ll be able to read a brief description of each fault code. It’s available on the forum. Just do a search.
I have already read all the post so I change battery and the problem still exist!
It seems the problem is electrical…The position sensor is trying to tell you something or else it might be the part that has failed. Whatever it is it doesn’t require a complete transmission replacement.
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Thank you very mush for your response! the batery is new! So I have to check the sensors?
Not necessarily.The transmission does have a voltage regulator. It’s located behind the battery. It is a part that seems to fail occasionally. Do a search on it to see if the symptoms described in those threads matches yours. Good luck for a cheap(ish) fix.
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We have done everything and now i take the car to test it! I dont feel to have problem with the change of gears! The battery its ok, we clean everything and we change the liquid!
the previous time i testedthe car, it was ok for about 200km and then the problem appeared again!
Also i dont have problem to change the gears from 1 to N to 1 to R.
How many km I have to do in order to understand if the problem fixed or not!
I’d give it 100km. Then you’ll know pretty surely that the problem is solved.
We change the oil and we check the battery and I check the car!
I have done 600km with no problems
Looking good!
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