Just a quick update on my "Christmas Tree of Death".... I have been doing some digging as to these kind of faults, and spent some time talking to the Alfa Technician here.

The basic root cause of the 'Christmas Tree of Death" is when a sensor gives a value that does not correspond with the other sensors. To put this another way using an example. If your throttle position is 100%, but engine speed is 700 rpm. Then you will get this "Christmas Tree of Death". There is typically lots of these cross checks that are occurring, so a fault in any one of these sensors could cause the issue. As others have noted, a low battery voltage could also cause the issue. In my case, the dealership has verified that I have a bad throttle position sensor and are replacing it. We will see if this completely solves the issue...

 

In my case, the dealership has verified that I have a bad throttle position sensor and are replacing it. We will see if this completely solves the issue...

How many miles (kilometers) on your 4C ?

 

@Racer Z Thank you for detailing your travails here! How many miles do you have on the car now? Hopefully the transmission has not given you problems since you got your software update ... has it?

Does anyone know if this software update made its way into a TSB? I recently got a 2015 LE, and I drive in dynamic + manual modes. The car has about 6K miles on it now and transmission works fine as far as I can tell (I did not buy it new, and I usually drive manuals so I don't have a good baseline for comparison).

Also, for folks who had experienced transmission issues, did any of you feel deterioration in how transmission worked prior to it malfunctioning completely or was it sudden (it seems like it was fairly sudden in a lot of cases)?

 

@Racer Z Thank you for detailing your travails here! How many miles do you have on the car now? Hopefully the transmission has not given you problems since you got your software update ... has it?

Does anyone know if this software update made its way into a TSB? I recently got a 2015 LE, and I drive in dynamic + manual modes. The car has about 6K miles on it now and transmission works fine as far as I can tell (I did not buy it new, and I usually drive manuals so I don't have a good baseline for comparison).

Also, for folks who had experienced transmission issues, did any of you feel deterioration in how transmission worked prior to it malfunctioning completely or was it sudden (it seems like it was fairly sudden in a lot of cases)?

Hi...
Current mileage: 39079 US Miles. Still my daily driver, well, that is when I don't need to use my work truck.
No, no and no.

• No, I've never had an issue since that software patch oh so long ago.
• No, it's never been made public, not that I know of.
• No, .... hmm

MIne was just "all of a sudden".

Not everybody has tranny issues. Enjoy the drive and don't worry about anything.




Oh yeah, Congrats on the used 4C LE.

 

@Racer Z Thank you, and thanks for the information. I've been lurking for a while, and I had seen this thread before I got the 4c. I am not that concerned about the transmission. I was trying to figure out whether I should go out of my way to get the dealer to update the software -- I'll just leave things the way they are.

 

Wanted to add a data point here - had an electrical brownout at my place while the car was on a trickle charger. Didn't think much of it, but on initial key-on a few days later, got a ton of "invalid data signal" errors. Cleared codes and cycled ignition - seems to have fixed, will be monitoring.

 

But we’re the corgis ok?

 

Hey folks! You can add my 2015 LE (~25k mi) to the CTOD list. Tried changing my battery out since it had never been replaced, and for good measure cleaned the terminals with a wire brush. Still continuing to get a U0415. I’ve also been receiving a U11DA:
Definition: Lost Driver Brake Torque Request Data, Cause:Antilock Brake System (Abs) Module Dtcs

Hesitant to go my dealership because I’ve had some really terrible service experiences with them (plus I’m out of warranty) but I may ask them to apply that secret software TCM patch that Racer mentioned.

Any other suggestions would be so very much appreciated!

 

I had (still have) a check engine light come on in my Giulietta (same engine and transmission as the 4C). After disconnecting and reconnecting the battery I got quite a few other faults appear including ABS failure. After driving for a while and a stop and restart at a petrol station the warnings disappeared. The only thing to reappear has been the check engine which is being investigated by my dealer as the car is under warranty. Awaiting another lambda sensor.

 

Ah best of luck @Alfanut ! Hope it turns out to be a quick and relatively simple fix for you. Did you manage to pull any error codes? Ha! I’ve started a thread on it just after Easter of this year. It has become an ongoing saga. I’m going to do a battery change as well but all battery tests come back as battery OK. The way it loses charge when not in use, I’m not too sure there isn’t something amiss with it. I’ve a code, but it’s the middle of winter here and I’m currently as warm as toast under the covers and going nowhere in month long lockdown with no immediate end in sight. I’ll post it when I can. Parts are not stocked by Alfa here and resulted in two lots of six-week waits, the current one I’m 3weeks into.

 

Just returning from a failry long drive and entering my street and a TPMS light came on. Then right after it said "No ABS Warning" (or similar). Then it said "No Airbags", by this point I'd parked in my drive and the engine cut out so I tried to start it again and got something like "Operation not available" or 'Can't complete operation". Car hasn't been used much over winter but has been charged up with a ctek. I went out again after 30mins and now the errors are all gone and the car starts.
Do I need a new battery?

 

Betting yes.
Model year? Original battery (if you know)?
First suggestion would be to ensure the terminals are tight. If you've never cleaned them, buy a $5 brush from an auto supply store and clean battery posts and wire terminals.
After that, I'd have battery and charging system checked. No point in waiting for the car to let you down. It's given you fair warning that something is amiss.

 

It's a 2015 Coupe and as far as I know is on the original battery. It might have been changed but I don't see it mentioned in any paperwork. Are there any particular batteries recommended.

 

Battery is also 3AH stronger compared to oem Mopar one...

 

Great thanks. I take it the spider battery and the coupe are the same then? I noticed that he didn't have the split rubber terminal cover that the coupe has.

 

Hi all, very appreciative of the wealth of knowledge on this forum — it helped me with my battery issue and I wanted to add my data point:

I have a 2015 LE, battery was replaced in 2022. Have put about 2300 miles on since the battery was replaced.

2 months ago:
Car sat for a month without a trickle charger, wouldn’t start. Used a battery jump starter and everything was fine for the couple drives I did.

1 month ago:
Car sat for another month, this time on a trickle charger. Wouldn’t start. Used a battery jump starter and all was fine. After 30 minutes of driving I shut the engine off. Car wouldn’t start. Used the jump starter again which worked but CEL appeared, and I was locked out of other drive modes.

Drove it home and then the Christmas tree appeared. Warnings for hill start, airbags, etc.

I came on this forum and got the car working again, here’s what I did:

1. Tested the battery voltage. 8.5 volts. Dead for sure.
2. Installed a new battery.
3. Removed a programmable exhaust controller that had stopped working properly a while ago and was likely causing parasitic battery drain.
4. Cleared the CEL with a scanner (code was P0685).

Car works perfectly again! Now I am monitoring the voltage regularly even with a trickle charger and will report back if any funny business continues.

 

^ After 200 trouble-free miles with the new battery, today I plugged in my OBD scanner (Autel AL319) to the car just to try out the scanner's features, but the scan itself triggered the Christmas tree and the warnings that the hill holder and ESC were unavailable. Additionally, the scanner showed the error code U0415 (invalid data from ABS).

Simply clearing the code with the scanner & then restarting the car removed all these warnings.

However, when I conducted another scan, the Christmas tree & all the other warnings came back, as did the code U0415.

I repeated this a few times: scan, clear code, restart car, all with the same results. I scanned with the engine off & key removed, with the engine off and ignition on, and with engine running -- same results.

Also, U0415 does not clear -- if I cleared the code then re-scanned right away, I'd just get U0415 again.

I suspect the issue could be with the OBD scanner, the OBD port, or potentially an actual problem with the ABS module (very open to anyone's ideas!). To eliminate the possibility of the Autel scanner itself being an issue, I plan to retry this with a different scanner (a Bluetooth unit with multiecuscan) and will update with the results.

Car is a 2015 LE with the original TCM software, an Alfaworks stage 1 ECU, GMS turbo-to-intercooler pipe, and some upgraded hoses.

 

Maybe replace your AW ecu with oem one to double check?

 

Back with an update now that I have an OBDLink MX+ device and the multiecuscan tool.

• Running an ECU scan or emissions readiness check does not find any fault codes, nor does it trigger the Christmas tree.
• Running a TCM scan finds code U0415-00 (error in communication with ABS module). Does not trigger the Christmas tree.
• Running an ABS module scan finds code "U0001-87 - C-CAN line error - Missing message". This triggers the Christmas tree. Mercifully as soon I disconnect the app from the ABS module, the Christmas tree disappears with no restart of the car required. I can confirm that I can enter dynamic mode at this point.

I googled the U0001-87 code and found this: https://static.nhtsa.gov/odi/tsbs/2020/MC-10185331-0001.pdf. It's a write-up of a similar issue with Land Rovers doing their version of a Christmas tree of death, where the problem is caused by damage to the wiring harness... so off to my mechanic this goes. The ABS and transmission still works fine btw, but I'd rather deal with this little gremlin before it turns into a bigger one.

@tibby -- really appreciate the suggestion. I think this finding is strong evidence that the ECU is okay however

This also means there is likely not an issue with my Autel AL-319 scanner, but my new setup gives me much more granular visibility (since I can connect to one computer at a time) which helped me isolate the problem.

Unrelated: while I was at it, I re-programmed the TPMS reference pressures to the correct values. Can confirm that the front reference pressure was incorrectly set to 29psi.

Again, super super appreciative of the wealth of knowledge on this forum and its helpful members!

 

Great information.
I’m pleased to read that you are getting somewhere with this.
Perhaps just corrosion on a connector, but now you / your shop have a system to focus on.
Good luck!

Also, interesting about the TPMS setting.

 

My experience with codes P2138, U11D4 and U0415

I have a 2015 none LE 4C with just under 15,000 miles. About a year ago while giving it the beans, it threw codes and went into limp mode. I simply turned it off then back on and it was good. Recently, it did this again. I pulled the codes and got the following: P2138, U11D4 and U0415. P2138 is correlation between TPS and accelerator pedal sensor issue. U11D4 is gas pedal signal issue. U0415 is invalid data from ABS control. I suspected the original battery so I replaced it with a nice new AGM one. Then it did it again, but I had to clear the P2138 code to be get the CELs to go away. It got worse then. I could not give the car any more than 10% throttle without it throwing the codes. Oh when it does throw the codes, it immediately cuts power and you better be in a position to pull over quickly because you have no power and are basically coasting slowly. I suspected the gas pedal because of the P2138 and U11D4 codes. I had my friend scan it with a much better Aultel unit and we could see the gas pedal signal at 77% when fully pressed and the throttle signal barely changing. This lead me to believe the throttle body was the issue. I removed and inspected it. It looked fine. I was able to get a used one from auto24parts.com for $160 shipped. It arrived in 5 days from EuropeI installed it and it made no difference. I then checked for 13 volts at the throttle body connector pins and 5 volts on the other pins there. Both were good. Decided to bite the bullet and took it to the local Alfa dealer. I picked it up yesterday and it was the gas pedal. It's a $800 Mopar part that Summit Racing will sell you for a little over $400.
I hope this info helps someone.

 

Hi 851duck,

Thanks for the info. I'm dealing with the same codes and everything I see is pointing to the gas pedal. I have an INNOVA 5610 scanner, and I can get a readout of the D and E signal move from approx. 13% to 88% and the TPS moves 12% to 14%. Do you know of where to get a parts list for the 4C?

 

The eLearn Manual for the 4C has parts codes all through it. I’m trying to find somewhere on the forum that has an operating link…It might take some time…If anyone knows of one please post the link.
Edit: i tried uploading my copy but the file was too large for this site to copy. Time for a site upgrade?

 

Just trying to catch-up on some of the posts.
I did get ten years out of my original battery. That's about twice the expected life. It was still working OK, but I decided not to press my luck.

Low system voltage will produce all kinds of erroneous errors. Check the system voltage, with engine off and while running, before chasing your tail round and round and round and...

 

@Scudrunner68 ,Post #23 in the link below will get you to the eLearn Manual but you’ll need to open a Microsoft account to open One Drive. I‘m unable to do any better.
https://www.4c-forums.com/threads/t...hreads/the-4c-cloud-table-of-contents.26921/page-3?post_id=1211017#post-1211017