[NortheastAlfaNut]

Good information.

To trigger these re-learns, they connected their system, or just disconnected the battery?

I assume the former (I think that the only transmission re-learn you can do without the diagnostic equipment is the "fine clutch adjustment", but would be happy to be corrected).

I am not entirely certain. The description in the service ticket reads:
"Per STAR, cleared all self learned data in TCM and performed quick clutch relearns. Road tested vehicle. Anomaly during shifting still present. Updated STAR with results. Per STAR, performed throttle body relearn and cleared all self learned data in ECM. Road tested vehicle. Anomaly no longer present in vehicle. Drove vehicle in all drive modes. Found vehicle shifting normally. Advise customer, vehicle tries to relearn operator's driving style and will change operation characteristics under aggressive driving."
Hope that helps!

 

[nate37]

@nate37 have you considered just replacing the TCU itself? Wondering if everything is actually fine, but there's just weird computer gremlins? The reason that I ask is, my understanding was that they won't sell the actuator or parts of the trans, and will only replace the full unit?

Well I'm trying to avoid just throwing (expensive) parts at the car, but to your point, a TCU is definitely cheaper than an actuator. You're also right that at this point I have no way of knowing whether the issue causing the fault is at the sensor or the TCU. Maybe if someone has a spare TCU laying around that they would let me borrow I could test that theory?

BTW, it is possible to buy the actuator separately: Clutch Hydraulic Unit Motor Mopar 68303710AA fits 16-18 Alfa Romeo 4C for sale online | eBay

I would take up Alfa Romeo Care up on their offer for help. In the background, with the details you have, they will reach out to their network to see if anyone solved a similar problem. I am a huge critic of service I receiver everywhere, but they are great and responsive.

Don't know what to say about the actuator gambit, other than Amazon has a good return policy. Maybe use it as nothing more than a test item to clear a variable? -- but I don't know about compatibility.

Yes, I agree. Been meaning to hit up @AlfaRomeoCares to see if they have any additional knowledge or could at least help me find a replacement sensor module, but haven't had a chance yet.

Were you able to rule out the wiring harness connections to the TCU (corrosion issue)?
I know that you said it wasn't likely from your ownership, but the car's past life and the heat where you live might have caused latent corrosion, just enough to cause this intermittent gremlin.

I would think this a worthwhile check before starting to disassemble parts of the transmission.

I haven't yet. My DIY timing belt change has been a disaster (see my other thread), so I'm still trying to get that sorted before I come back to this issue. Once I finish the belt (almost done) I plan to take off the driver side quarter panel so I can inspect the TCU connections, chassis ground connections, and as much of the actuator wiring harness as I can get to. Definitely doing this before I start taking the transmission apart. From what I can see, removing the actuator might be a pain. Not a lot of room to maneuver it out.

Good information.

To trigger these re-learns, they connected their system, or just disconnected the battery?

I assume the former (I think that the only transmission re-learn you can do without the diagnostic equipment is the "fine clutch adjustment", but would be happy to be corrected).

I know that my Foxwell reader has the all the transmission re-learns included in it, and it looks like there are several re-learn procedures for the ECU also. Seems like the easiest way to do it.

 

[nate37]

Just following up here and hopefully turning the page on this issue. I took my car up to Las Vegas to have Towbin Alfa Romeo service it, since they had recently fixed a similar problem on another forum member's car. After a lot of diagnosis (they could never reproduce the faults, go figure), we eventually decided to replace the transmission hydraulic actuator. This was based on the fault codes I had saved, the fact that replacing the actuator fixed the other car that was throwing a similar code, and also based on some back-to-back drives the dealer did with another 4C, where they noted the shift quality was worse in my car.

Happy to report that I picked the car up from the dealer and drove it back to Phoenix yesterday (~300 miles) without issue. The dealer put another ~50 miles on it to verify the repair, so I'm over 350 miles now, where previously I was seeing the fault every 5-100 miles of driving. The car also shifts MUCH better than before, with a lot less clunkiness in both manual and auto modes. I didn't realize how bad it was before, since it had been that way for the entire time I've owned it (since last Jan). So I'm very hopeful the bad actuator was the issue and I can start to enjoy this car again! I'll post back here if this same issue crops up again, but just wanted to get this info out here in case anyone else runs into a similar problem in the future.

Also, major shout out to Towbin AR, who were awesome to deal with. They had excellent communication throughout the whole process and did absolutely everything they could to diagnose the root cause before just throwing parts at the car. Their pricing was also more than fair given how many hours of diagnosis they had into it. They're by far the best AR dealer service department I've interacted with and are now pretty knowledgeable on this problem, so I would highly recommend them for anyone else on the West Coast who runs into this issue.

 

[rikiduc]

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.

Hi, My 4C has 70.000 Km and I experience the same problems now. I am using the Multiscan 4.7R3 tool and did all Adjustements. In the Production/Service final calibration procedure, all elektrovalves, potentiometers and mechanical components of the whole actuation unit, are tested. So, in your case, it would also test the integrated sensor module. So my suggestion is to run this test and than do the clutch self-calibration enable. In my case I first got the error code related to the electropump of the power unit. I changed the electropump,the accumulator and the elektronic control unit of the elektropump, but without any succes. During a trip in the Italian mountains, I got the same problem. Now I am going to replace the clutch, because with 70K and at least 50% driving in the mountains, I think the best is gon and the clutch is worn.

 

[nate37]

Hi, My 4C has 70.000 Km and I experience the same problems now. I am using the Multiscan 4.7R3 tool and did all Adjustements. In the Production/Service final calibration procedure, all elektrovalves, potentiometers and mechanical components of the whole actuation unit, are tested. So, in your case, it would also test the integrated sensor module. So my suggestion is to run this test and than do the clutch self-calibration enable. In my case I first got the error code related to the electropump of the power unit. I changed the electropump,the accumulator and the elektronic control unit of the elektropump, but without any succes. During a trip in the Italian mountains, I got the same problem. Now I am going to replace the clutch, because with 70K and at least 50% driving in the mountains, I think the best is gon and the clutch is worn.

Sorry to hear you're having the same issues. I suspect we will see more cars have this problem as time goes on. Good idea on the testing - hopefully that helps someone in the future.

In my case, the electropump was fine. The hydraulic actuator was the issue. With a new actuator, the car shifted much more smoothly and no more errors. I have about 2,000 mi (~3200 km) on the new actuator and have had zero problems. Did you get the same trouble codes as I originally got (P1C9900)?

I would suggest looking into the actuator before clutch replacement. Or, at the very least, inspect the clutch and if it's not worn, I would look hard at the actuator. In my case, the dealership was able to pinpoint the problem by driving my car back-to-back with another 4C and the difference in shift quality was immediately noticeable. That plus their previous experience replacing the actuator to resolve the same codes, led them to replace the actuator on mine. I know back-to-back test drives is not always doable, but they got a little lucky.

 

[rikiduc]

Thanks for the info!

 

[Launch-459]

Sorry to hear you're having the same issues. I suspect we will see more cars have this problem as time goes on. Good idea on the testing - hopefully that helps someone in the future.

In my case, the electropump was fine. The hydraulic actuator was the issue. With a new actuator, the car shifted much more smoothly and no more errors. I have about 2,000 mi (~3200 km) on the new actuator and have had zero problems. Did you get the same trouble codes as I originally got (P1C9900)?

I would suggest looking into the actuator before clutch replacement. Or, at the very least, inspect the clutch and if it's not worn, I would look hard at the actuator. In my case, the dealership was able to pinpoint the problem by driving my car back-to-back with another 4C and the difference in shift quality was immediately noticeable. That plus their previous experience replacing the actuator to resolve the same codes, led them to replace the actuator on mine. I know back-to-back test drives is not always doable, but they got a little lucky.

When you were having issues was reverse available? My car is currently in the shop and I am trying to help the tech with any guidance as far as known issues.

 

[nate37]

When you were having issues was reverse available? My car is currently in the shop and I am trying to help the tech with any guidance as far as known issues.

Ah sorry to hear you're also having issues. When my car would fault I would lose R, 1, 3, and 5. These gears are all on the same shaft, so my guess is that the gear position sensor on this shaft would fault and the TCM would lock out all those gears to preserve the transmission.

You might have your dealer call Towbin AR in Henderson, NV, since they have experience fixing this problem on at least two cars now.

 

[Launch-459]

Ah sorry to hear you're also having issues. When my car would fault I would lose R, 1, 3, and 5. These gears are all on the same shaft, so my guess is that the gear position sensor on this shaft would fault and the TCM would lock out all those gears to preserve the transmission.

You might have your dealer call Towbin AR in Henderson, NV, since they have experience fixing this problem on at least two cars now.

Thanks, I'll let the dealer I'm working with know.

 

[rikiduc]

Sorry to hear you're having the same issues. I suspect we will see more cars have this problem as time goes on. Good idea on the testing - hopefully that helps someone in the future.

In my case, the electropump was fine. The hydraulic actuator was the issue. With a new actuator, the car shifted much more smoothly and no more errors. I have about 2,000 mi (~3200 km) on the new actuator and have had zero problems. Did you get the same trouble codes as I originally got (P1C9900)?

I would suggest looking into the actuator before clutch replacement. Or, at the very least, inspect the clutch and if it's not worn, I would look hard at the actuator. In my case, the dealership was able to pinpoint the problem by driving my car back-to-back with another 4C and the difference in shift quality was immediately noticeable. That plus their previous experience replacing the actuator to resolve the same codes, led them to replace the actuator on mine. I know back-to-back test drives is not always doable, but they got a little lucky.

see also my other new posted treath:
Testing and repair of clutch position sensor

 

[Gilly]

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.

Yes, I should add the TCM as a potential culprit. I will definitely pull off the shield and connectors and inspect the connections for water intrusion, but I'm guessing it's not the issue here (see below).



I put the car on a Battery Tender after the first occurrence just in case, but it didn't prevent the last two happenings. I'm still keeping the battery on the list of problem areas though. The AZ heat is known to kill batteries and if this is the factory battery, it's end-of-life anyway.



I could definitely see this being an issue, as I actually lived through this problem (water intrusion via wire harnesses) with an automotive component I designed at my job several years ago. However, I would be surprised if it's the problem here - I live in AZ where it's very dry all the time, and when I wash the car I use Optimum No-Rinse, which means that I don't even hose the car down. So if any water is getting in the engine bay, it's a few drops at best. The car did come from Florida and Virginia though, so it's not impossible there was existing corrosion before I bought it.

Nate - There are some clues in what you describe that lead me to believe it is more voltage / input error related than mechanical. The clutches for even and odd gears are controlled separately with the odd via a distance sensor and the even via a pressure sensor any fault with these would show up as an even or odd gear unavailable and no manual shift.
If the actuator fluid level is ok then I wouldn’t touch this other than a minor top up - it could add another set of variables to your problems..

The fact yours come up with Christmas tree errors on start up suggests voltage or earthing issues or a TCU problem. Early models did not have a rain shield fitted over the TCU which sits directly under and gap in the panels and drip line. Water ingress to the top of the TCU plugs could definitely cause a short - have a look for signs of water ingress and pull the plugs out and inspect they are dry and not corroded. Install a make shift rain shield over the TCU. If the battery is more than 3-4 years old I’d get a replacement anyway just to rule it out and I’d go and inspect all the earthing point and make sure the terminal posts / fasteners are tight and corrosion free.

The next thing to do would be aTCU swap and if there is still problems then it’s time to start looking at the transmission itself…

 

[Gilly]

Just following up here and hopefully turning the page on this issue. I took my car up to Las Vegas to have Towbin Alfa Romeo service it, since they had recently fixed a similar problem on another forum member's car. After a lot of diagnosis (they could never reproduce the faults, go figure), we eventually decided to replace the transmission hydraulic actuator. This was based on the fault codes I had saved, the fact that replacing the actuator fixed the other car that was throwing a similar code, and also based on some back-to-back drives the dealer did with another 4C, where they noted the shift quality was worse in my car.

Happy to report that I picked the car up from the dealer and drove it back to Phoenix yesterday (~300 miles) without issue. The dealer put another ~50 miles on it to verify the repair, so I'm over 350 miles now, where previously I was seeing the fault every 5-100 miles of driving. The car also shifts MUCH better than before, with a lot less clunkiness in both manual and auto modes. I didn't realize how bad it was before, since it had been that way for the entire time I've owned it (since last Jan). So I'm very hopeful the bad actuator was the issue and I can start to enjoy this car again! I'll post back here if this same issue crops up again, but just wanted to get this info out here in case anyone else runs into a similar problem in the future.

Also, major shout out to Towbin AR, who were awesome to deal with. They had excellent communication throughout the whole process and did absolutely everything they could to diagnose the root cause before just throwing parts at the car. Their pricing was also more than fair given how many hours of diagnosis they had into it. They're by far the best AR dealer service department I've interacted with and are now pretty knowledgeable on this problem, so I would highly recommend them for anyone else on the West Coast who runs into this issue.

Great to see the fault resolved! The actuator fault is not an uncommon issue among a number of brands. Audi / VW’s have a known weakness in their hydraulic actuator assemblies within their DsG boxes. Reading the service manual functional description of the transmission gives you an appreciation for how complex these things are and how many different degraded / limp modes they can go into depending on the root cause…

 

[gkardr6]

Hello, My name is George from Greece and I own a 2015 4C. I have the same promlem with transmision. I already 35.000km. After driving 45km the gear box goes to safe mode and I can the car goes to auto and use only the 2nd 4th and 6th gear. when I go back home and leave it all night, the next day its everything fine! I drive about 50km and the issue appeared again! do I have to change all the transmision? The failure coed is P0914 any ideas

 

[Philster]

Hello, My name is George from Greece and I own a 2015 4C. I have the same promlem with transmision. I already 35.000km. After driving 45km the gear box goes to safe mode and I can the car goes to auto and use only the 2nd 4th and 6th gear. when I go back home and leave it all night, the next day its everything fine! I drive about 50km and the issue appeared again! do I have to change all the transmision? The failure coed is P0914 any ideas

We are obliged to ask, since this is an electrical error code, if you are on the original battery or if you have a newer battery that has been cared for.

 

[gkardr6]

I have already read all the post so I change battery and the problem still exist!

 

[Alfanut]

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.

 

[gkardr6]

Thank you very mush for your response! the batery is new! So I have to check the sensors?

 

[Alfanut]

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.

 

[gkardr6]

Ι will try and I give you a feed back!
Thank you very much!

 

[rikiduc]

The position sensors are together in a module that is part of the robot. This module is not available separately. The chance of these breaking is also very small, but it may be that they are soiled with small metal particles that come out of the gearbox. The robot is fairly easy to disassemble.
The sensors themselves can be tested, with the Multiecuscan it is possible to operate the robot and test all gears without the motor running. The position sensor of the clutch or the position sensor of the shifter can also be a cause here.
The entire system is also tested during a recalibration of the robot / gearbox. So I would do these tests first.
I would certainly change the oil of the gearbox and definitely the oil and filter of the robot (after cleaning the sensors)
The pictures show you the sensor module disassembled and the robot with the module mounted.
What you should also do is check the electrical wiring and treat the connectors on the robot and the TCU with a good contact spray.