2018-2019 Leaf 2.0 "Service EV System. Unable to restart after power off"

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It is, but alas, Nissan did a poor job of programming the charging system, and weak, undercharged (12.0 volts is nearly dead) 12 volt batteries are a very common problem. You want to avoid leaving the car plugged in for hours after charging ends, because that, ironically, runs down the 12 volt battery. You also can't rely on the car to charge up the 12 volt battery whenever it gets low, because that doesn't happen with perfect reliability in all situations.
 
I doubt that there was anything wrong with the A/C compressor or PTC heater. A true battery isolation DTC indicates insulation breakdown somewhere in the high-voltage system, but a weak 12V battery can cause multiple DTC's due to CAN Bus communication errors. Check the voltage at the 12V battery terminals with an accurate meter while the car is in ready mode. It should be at least 13 volts, higher at colder temperatures and about 14 volts if windshield wipers are on. A true battery isolation fault is not likely to clear by itself so I still suspect the 12V battery is weak or something else is interfering with CAN bus communications.
 
I replaced the 12v back in July 2022, but I’ll do a warranty swap on it and hope for the best. Do the lithium 12v I’ve heard people use standup better? I too am not convinced the A/C or Heater had issues at such low mileage, but I didn’t have any other options for a 2nd opinion in my area.
 
LeftieBiker : ' . .. leaving the car plugged in for hours after charging ends, because that, ironically, runs down the 12 volt batt ..

TiredLeafer: “The voltage reading on the 12v was 12.0v.” Isn’t the 12v battery supposed to charge when the car is plugged in at night?

Me (ReptonAU) : The 12V battery is weak, as it was drained not because it is faulty or bad

GerryAZ : '' .. .. … a weak 12V battery can cause multiple DTC's due to CAN Bus communication errors.”

I believe this includes the erroneous PA006, which bricks the car and presents the Service EV msg.

A drained battery is not equal to a bad battery.
Don't blame a perfectly fine 12V battery if Nissan:
AND drains the 12V
AND fails to recharge the 12V
AND bricks the car because the 12V is not charged.
 
You were all right, it wasn’t a specific issue with the heater or a/c compressor. They finally did what I asked and checked the battery, and lo and behold, issues with the battery control module and individual cells. I’ll be getting a refund on at least some of my previous repair costs.
 
Dear all,

Both my father and I have the same issue with our Leaf model which was bought in 2022. My father's Leaf was repaired 3 or 4 times and the last thing they did is replace the battery mobilizer/control module or whatever it is. This morning he had the same issue and he took it back to the dealer. My car is at the dealer too since last week with the same issue! They are seeing all of this with the manufacturer because we cannot trust the car anymore now! I think Nissan has a manufacturing fault somewhere and they do not know what it is to repair!
 
There should be a concerted effort here to try to pin down what year build this started. There have been issues with bad cells since the first Gen II cars were sold, but it seems to have spiked at some point...
 
Yes, a weak or discharged 12 volt battery can be caused by long periods of the car being connected to charge but not charging - usually the charge has finished and the cable just sits there, leaving the car to keep verifying the connection, which uses power, and also not being charged by the car. If the cable must be left on for hours after charging ends, then a battery maintainer will prevent the 12 volt battery from getting too low.
 
“. . . . . .then a battery maintainer will prevent the 12 volt battery from getting too low. “

TiredLeafer in an earlier post confirmed that this did not happen. So the software that is supposed to initiate the charging of the 12V (the battery maintainer?) is not doing its job. So what has the 12V battery done wrong? What can be blamed on any piece of hardware? Recharging the 12V is ONLY a problem after the HV is switched off (end charging} with a cable left connected. ALL problems are fixed as soon as the 12V is recharged (and DTCs reset). If ALL pieces off hardware are being replaced and the problem still keeps happening is there a change that the software one day will loose its presumption of innocence?
 
TiredLeafer41 said:
I replaced the 12v back in July 2022, but I’ll do a warranty swap on it and hope for the best. Do the lithium 12v I’ve heard people use standup better? I too am not convinced the A/C or Heater had issues at such low mileage, but I didn’t have any other options for a 2nd opinion in my area.

My 12V lithium is +8 years old now, still working in it's second Leaf. I transferred it from my 2013 to my 2020 and just put the lead brick in storage in case I needed it for something else. Last test I did, it's still working at around 80% of it's original capacity. If you find a good quality Lithium, it's worth it in the long run both maintenance and headaches wise. ;)
 
LeftieBiker said:
Yes, a weak or discharged 12 volt battery can be caused by long periods of the car being connected to charge but not charging - usually the charge has finished and the cable just sits there, leaving the car to keep verifying the connection, which uses power, and also not being charged by the car. If the cable must be left on for hours after charging ends, then a battery maintainer will prevent the 12 volt battery from getting too low.

Sounds like I should do an experiment to measure how much "vampire" power is being drained from the 12V battery in this state. Using that, one could calculate how long the battery will have before it's too drained to start the Leaf, cause all the CAN bus errors, etc. :cool:
 
You'd need several (at least) Leafs to test, to see if there is consistency. From memory, it seems that there is a typical vampire drain that a typical battery maintainer can overcome, and then there is the vampire drain where relays stick or otherwise stay open, and the car uses enough power when off to kill the 12 volt battery despite having a little 0.75A maintainer working to counter it...
 
LeftieBiker said:
You'd need several (at least) Leafs to test, to see if there is consistency. From memory, it seems that there is a typical vampire drain that a typical battery maintainer can overcome, and then there is the vampire drain where relays stick or otherwise stay open, and the car uses enough power when off to kill the 12 volt battery despite having a little 0.75A maintainer working to counter it...

Currently, I have a 2020, 2018, and 2015 to test with. Not every possible year, but at least a good start. :mrgreen:
 
Just want to add my experience since this thread helped a bit in a recent situation. We have a 2021 Leaf S Plus and e just took a road trip to Quebec for vacation (we're in the US) and hit this issue.

We got the error code after turning the car on the morning after our first hotel stay there. As we were afraid that turning the car off would probably leave us stranded wherever we were, we headed right to the Nissan dealership there. Sparing all the issues with trying to navigate the service department, basically they determined they just needed to replace the 12 volt battery. They did that, the warranty covered it, and it has been running fine in the few days since.

In drilling down, I am wondering about LeftieBiker's explanation below. We have never had any issue with our Level 2 charger at home, but that night at the hotel we charged it at the Level 2 charger at the hotel overnight. What is making me think is that the charger was not charging by the amount of power transferred, rather the amount of time that the charging plug was not in the holster. That makes me think that the charger kept sending pings or whatever (pardon the non-technical terms) to the car and drew down the 12 volt as per the explanation below.

So, just to add this experience to the discussion if helpful to anyone at all in figuring it out. Thanks!

LeftieBiker said:
Yes, a weak or discharged 12 volt battery can be caused by long periods of the car being connected to charge but not charging - usually the charge has finished and the cable just sits there, leaving the car to keep verifying the connection, which uses power, and also not being charged by the car. If the cable must be left on for hours after charging ends, then a battery maintainer will prevent the 12 volt battery from getting too low.
 
Finally got my vehicle back from the local Nissan dealer. They replaced the battery pack under warranty, just lied to me about what they were doing. Anyone want to buy a 2018 S trim with 31,200 miles or a HV battery with 99.5% SOH? The vehicle now reports 190 miles of range with Summer tires on at a 100% charge.
 
Pretty sure. Started this fiasco with a SOH around 91%. I get it back from the dealer after they finally check the HV battery and identify an issue with the battery pack. I get it back with a SOH of 99.5%.
 
It is also quite possible that they just reset the Battery Management System (BMS) and that magically restored the missing health - at least until the battery readjusts and reestablishes the SOH...
 
Just this morning, I got "Service EV System. Unable to restart after power off". It's Sunday, so the dealership is closed. I took the 12V battery in to be tested and it checked out OK.

I have a 2019 Nissan Leaf SV with 48,000 miles on it. After reading the other posts, I'm dreading what's coming up. I'll check back in when new information comes out.

Update: The dealer towed the car in and checked it out. They said the main battery needs to come out and either a module needs replacing or the whole pack will need to be replaced. The estimated timeline in 2 weeks+. They have provided a loaner vehicle (it's a rental covered by the warranty, to be precise.)

Overall, while I'm disappointed that this happened, I have a few blessings to count: 1) It happened at home. 2) Nissan has been very receptive and accommodating.

Aug 5 update:

The dealership said they replaced the battery and the receipt also says they did a VCM reprogram.

All in all, I'm surprised it happened so quickly. I am very thankful for how the dealership treated the problem and how they treated me.
 
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