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Fault messages and no more regeneration

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2.6K views 37 replies 7 participants last post by  Electric Tire Shredder  
#1 ·
Hello everyone,
After replacing my 12V battery, I'm getting a ton of error messages (I didn't wait long enough before connecting the new battery). I've tried many resets (as indicated in the forum, but nothing worked). Yesterday, I disconnected the 12V battery until at least Sunday. I hope that will solve the problem.
 
#4 ·
In a 2020+ 500e, basic OBD like a Bluetooth dongle & the MultiEcuScan.info app won't clear any fault codes, it will only read them, but even for that the 12V must be connected & the car turned on.

At that point, the first step is to pair the phone with the dongle. If that doesn't work, then the issue is with the phone &/or dongle. There are a couple of recommended setups under "OBD Basic" at my "Site Map" (click here).
 
#5 ·
I didn't wait long enough before connecting the new battery
You're only supposed to wait 5+ minutes between disconnecting the old one & connecting the new one. That will ordinarily happen on its own by the time you get the old one out & the new one in & both terminals connected.
 
#6 ·
I've tried many resets (as indicated in the forum
There are only two resets that I know of:
  • 12V-Only
  • 12V-&-HV
Detailed instructions for both of those are also at the "Site Map".

If you know of other resets please let me know.

Yesterday, I disconnected the 12V battery until at least Sunday. I hope that will solve the problem.
That's worth trying, because when a 5-minute disconnect doesn’t fix issues in pre-2020 cars, 30+ hours often does, & when that failed, 61 hours has worked for at least 2 cars that I know of so far.

However, often 30+ hours with just the 12V off doesn't work unless the HV is also off ("12V/HV Reboot").
 
#11 ·
Even better: 61+ hours has worked for at least two pre-2020s that I know of, after 30+ hours did nothing.

Apparently there are capacitors &/or other components which retain power for quite a while, preventing a real cold, hard reboot.

Some OTHER vehicles can do an instant capacitor discharge with the 12V disconnected & shorting the positive & negative clamps to one another, but that might fry a 500e.
 
#12 ·
I hope 61 hours works on my 2021...
I hope I didn't damage a computer by reconnecting the battery too quickly.
When it happened, I heard a cycling switch noise and couldn't get the car to start again.
So I reconnected the battery, waited about an hour, and was able to get the car started again.
 
#15 ·
Even after disconnecting the 12V battery for 77 hours, the alarms are still present. I also have the "initial" alarm (checked the door locking system) which has returned, with the inability to lock the car; you also have to put the key in the compartment between the seats to start the car.
I think the key is not being detected by the vehicle.
Before I replaced the battery, this was the only alarm present.
Then, a "quick" battery replacement generated all the other alarms.
 
#16 ·
Would it be too simple to presume that the key fob not being detected by the car is the root cause of your remaining issues?

Am I right to believe that you can start and drive the car, if you put the key fob in the central compartment?

You might try replacing the battery in the key fob and see if that makes any difference. Or try your second key if you have one.
 
#17 ·
No, the control for key's batteries are fine, and I also got a "low battery" message.

Continuation of the story:
After a round trip of a few miles, all the faults except for the "checked the door locking system" message disappeared.:)
I disconnected and reconnected the battery again and... miraculously, it also disappeared, and I can lock the car again.
I hope it's okay this time. I think disconnecting the battery for over 60 hours, then driving a bit, helped reset the computer.
I'm still wondering about the fault with the door locks; maybe the 12V battery was starting to get old...
 
#18 ·
I also got a "low battery" message.
If you mean a "low 12V battery" message, it may have gone low enough to cause the glitches you experienced.

I believe there was a dealer-installed software update that affected the 12V.

If you already have that, you might consider adding your own ~$30 Bluetooth battery monitor like an Ancel.com BM200 to give you some advance warning to prevent it happening again.
 
#26 ·
There were 2 issues in early 2nd generation cars until they got recall 6475.

The 12V battery could go flat without any warning.
If the 12V battery was disconnected and reconnected, the car had lots of alarms and couldn't be started.

My La Prima was built in late 2020 or very early 2021. In mid 2022 it died and had to be recovered to the dealer. The dealer found no faulty parts and did the software update of recall 6475 and the car has given no trouble since. Even though I've needed to disconnect the 12V battery a couple of times.
 
#27 ·
Since yesterday, I've recovered all functions, and the alarms have disappeared. But the initial problem has reappeared:
"Have the door locking system checked." That's the message I initially received. You can no longer lock the car from the outside and you have to put the key in the compartment between the seats.
The remote control battery is good.
The problem sometimes disappears.
I have the impression that the key isn't detected.
Disconnecting the 12V battery resets the message, but it comes back...
 
#29 · (Edited)
  • You have a warning for low key fob battery, as if the key fob battery is low.
  • Your key fob doesn't lock or unlock the car, as if the key fob battery is low.
  • Your key fob only starts the car when it's in the center compartment, as if the key fob battery is low.
I wonder if you've actually tested the key fob battery with a multimeter.

Several owners have had problems with brand new key fob batteries. Off-brand seem worse, but even a name-brand battery could be defective.