2012 Leaf not charging; Lithium cell bad; 12 volt ok

Hello. I have a 2012 Leaf. The original battery was replaced with a refurbished battery in 2016; there was only a 1-year warranty. This week the EV Warning System light came on. I could start the car but it would not shift out of neutral. When I plugged it in to charge, it would not charge. The 12-volt battery tested a little low, so I replaced it with a new one. The car started and I was able to shift into Drive. Turned off the car to charge it but it would not charge, and the EV Warning System light came back on. I have LeafSpy, and I when I clear the error codes the car will start and shift into Drive, but when I try to charge it the warning code returns and the car won’t charge. I took the car to the dealer, who said there is a bad cell in the lithium battery. I was quoted $15,000 to replace the battery ($13,650 for the battery, plus labor and tax.) (NOTE: I live in Hawaii, so slightly higher prices are expected, but not that high. I am aware that as recently as June 2020 new lithium batteries were around $6,000 installed.) I called a different dealer, and was quoted around $11,000 ($9,600 for the battery, plus labor and tax.)

Paying that much is not possible for us. My questions are: Does anyone know if it is safe to drive the car with a bad cell? And if so, is there a way to charge the car? It seems that as soon as we plug it in, the diagnostic codes prevent the car from charging. Are there any other options I haven't thought of?

And input is welcome. Thank you.

That is INSANE!

At those kind of prices, I'd dump the car and buy a used EV for cheap. Take a look at how much Bolts are: https://www.cars.com/for-sale/searchresults.action/?mdId=36274172&mkId=20053&page=1&perPage=20&rd=99999&searchSource=SORT&sort=price-lowest&stkTypId=28881&zc=95032. Given that you live in Hawaii, I'm not sure you'd even care if the car didn't have a DC fast charging inlet.

Let us know what the DTCs are. How much imbalance (in mV) are you seeing in Leaf Spy? Let us know the % SoC when you indicate the imbalance.

Thank you for responding. I agree, insane. But it also does not make sense to trash an otherwise perfectly good car. If we have to clear codes each time we drive it, that's fine. But we can't do that without a way to charge it, or assurance that it's safe to do that.

I don't seem to have the ability to attach an image, so I will list DTC codes here:

P31E7 00C0 EV/HEV Restart Inhibition EVC-310
P0AA6 00CC EV/HEV Hybrid Batt Volt Sys Isolation EVC-157
B2722 0018 HVAC PTC Heater Voltage HAC-75
B2777 0018 HVAC PTC HTR LIN Comm HAC-84
B2779 0018 HVAC PTC HTR Comm HAC-84
B277A 0018 HVAC PTC HTR Connector HAC-86

I apologize that I can only describe the cell imbalance, taken at SOC=57.7%; 7 cells are just above 3.960, the rest are between 3.965 and 3.98, with most around 3.97.

The car is at the dealer's now, so I can't provide much more information. What I have here are screen shots we took before taking it to the dealer. Thanks again.

That looks like an isolation fault, maybe a bad PTC heater, more than a bad cell.

I agree -- not a bad cell.

Find a dealership who are not idiots

lavaleaf said:

Thank you for responding. I agree, insane. But it also does not make sense to trash an otherwise perfectly good car. If we have to clear codes each time we drive it, that's fine. But we can't do that without a way to charge it, or assurance that it's safe to do that.

I don't seem to have the ability to attach an image, so I will list DTC codes here:

P31E7 00C0 EV/HEV Restart Inhibition EVC-310
P0AA6 00CC EV/HEV Hybrid Batt Volt Sys Isolation EVC-157
B2722 0018 HVAC PTC Heater Voltage HAC-75
B2777 0018 HVAC PTC HTR LIN Comm HAC-84
B2779 0018 HVAC PTC HTR Comm HAC-84
B277A 0018 HVAC PTC HTR Connector HAC-86

I apologize that I can only describe the cell imbalance, taken at SOC=57.7%; 7 cells are just above 3.960, the rest are between 3.965 and 3.98, with most around 3.97.

The car is at the dealer's now, so I can't provide much more information. What I have here are screen shots we took before taking it to the dealer. Thanks again.

Click to expand...

Yeah, sounds like the isolation fault and heater probs might be the issue. The heater does run off the high voltage bus.

Re: imbalance, if you have screenshots of the cells screen, it should at the bottom list min and max voltages. Also, in ( ) and also in the upper right in larger font, it'll show imbalance in mV. What are the min and max voltages along w/imbalance mV?

The key is even one is WAY off from the others, that'll cause a problem but I've not heard of charging problems, usually causes weird range collapse issues (e.g. turtle way too early or at pretty high SoC like 50+%) and shows up in Leaf Spy like https://www.mynissanleaf.com/viewtopic.php?p=457964#p457964.

If this is a faulty PTC heater, can it simply be disconnected ? I presume it would not be missed in HI

I recall reading a thread at https://www.facebook.com/groups/seattlenissanleaf where the well-known tech (Aaron) described one of his elaborate diagnosis and repair jobs. Might've been an isolation fault/shorting of some sort. I'm having trouble finding it. Was posted at least a year or two ago.

Here's a interesting one involving a '19 Leaf: https://www.facebook.com/groups/seattlenissanleaf/permalink/2880751448622940/.

Here we go, https://www.facebook.com/groups/seattlenissanleaf/permalink/872430932788345/ might've been it. You'll need to view comments to see what Aaron wrote. That type of diagnosis would be impossible for a DIY mechanic at home w/o the service manual and probably w/o Nissan Consult III Plus. Here are some relevant comments:

This car had a high voltage "leak" that blew the fusible link portion of the H/V relay box. I do have the full assortment of insulated tools.
...
So the A/C compressor had a minor high voltage leak to ground. Unfortunately this also damaged the Traction motor inverter. The fix ended up being new A/C compressor, new inverter and a junction block.
...
Correct. Fuse blew and that leaves the system main relays unable to engage.
...
It was a long process. I feel bad for the customer. This car ended of being down for 45 days. The diag procedures provided to the techs need some rewriting. The inverter and one junction block where replaced first. As soon as I powered the car up after the initial repair the block blew again and threw all the original codes. The way the manual is written it does not show any correlation between the A/C compressor and inverter. It took a lot of book work,the better part of Nissans Leaf Task force and some insight by my DTS (District Tech Supervisor) to get this car back on the road again.

Click to expand...

cwerdna said:

lavaleaf said:

Thank you for responding. I agree, insane. But it also does not make sense to trash an otherwise perfectly good car. If we have to clear codes each time we drive it, that's fine. But we can't do that without a way to charge it, or assurance that it's safe to do that.

I don't seem to have the ability to attach an image, so I will list DTC codes here:

P31E7 00C0 EV/HEV Restart Inhibition EVC-310
P0AA6 00CC EV/HEV Hybrid Batt Volt Sys Isolation EVC-157
B2722 0018 HVAC PTC Heater Voltage HAC-75
B2777 0018 HVAC PTC HTR LIN Comm HAC-84
B2779 0018 HVAC PTC HTR Comm HAC-84
B277A 0018 HVAC PTC HTR Connector HAC-86

I apologize that I can only describe the cell imbalance, taken at SOC=57.7%; 7 cells are just above 3.960, the rest are between 3.965 and 3.98, with most around 3.97.

The car is at the dealer's now, so I can't provide much more information. What I have here are screen shots we took before taking it to the dealer. Thanks again.

Click to expand...

Yeah, sounds like the isolation fault and heater probs might be the issue. The heater does run off the high voltage bus.

Re: imbalance, if you have screenshots of the cells screen, it should at the bottom list min and max voltages. Also, in ( ) and also in the upper right in larger font, it'll show imbalance in mV. What are the min and max voltages along w/imbalance mV?

The key is even one is WAY off from the others, that'll cause a problem but I've not heard of charging problems, usually causes weird range collapse issues (e.g. turtle way too early or at pretty high SoC like 50+%) and shows up in Leaf Spy like https://www.mynissanleaf.com/viewtopic.php?p=457964#p457964.

Click to expand...

Thank you for these suggestions. The information you asked for is below. Would this have been enough for them to claim a faulty cell?:

Min/avg/max = 3.961 / 3.969 / 3.982 (21mV)

Thank you for all your responses. Until I receive a copy of the fault codes they generated, I will not know why they are claiming a bad cell. The rep did not say anything about a bad PTC heater. The diagnosis set us back $185, but we won't be dealing with them further, either for a repair or for a different car.

If it is indeed a leaky or faulty cell, it does not sound safe to drive, so I will let go of that idea. When I pick it up, I will ask about disconnecting the PTC heater.

That 21mv difference is nothing - there is no evidence so far of a bad cell. See Cwerdna's post for another possibility.

lavaleaf said:

Min/avg/max = 3.961 / 3.969 / 3.982 (21mV)

Click to expand...

21 mV is TOTALLY within the norm. That wouldn't trigger a turtle nor warning light.

Interesting that you don't feel that's enough to trigger a turtle or warning light. Good to know, thank you. Maybe the issue really is something else. Sounds like I need to get a copy of the codes the Nissan dealer generated. I don't have confidence in the service person I spoke with. When I asked about the possibility of fixing just the damaged cell, he started talking about how "they don't do that because of the radiation and the special training and suits they have to wear." Huh??

They are lying to you. Get to another dealer ASAP. I doubt they would have replaced a cell - just charged you thousands for a job not needed and not done.

Interesting that you don't feel that's enough to trigger a turtle or warning light.

Click to expand...

You don't understand. It isn't a question of "enough" - you apparently, according to the info provided, have a good normal pack with NO BAD CELLS.

lavaleaf said:

Interesting that you don't feel that's enough to trigger a turtle or warning light.

Click to expand...

Not a feeling, it is a certainty.

Look at this graph



You can flip the numbers on the X axis to imagine the discharge from full to empty. If you add a zero to the voltage on the Y axis, that is pretty close to cell voltage in milliVolts (mV). **

Good luck identifying the difference in discharge between 3700 and 3680. You can also note that a normal cell voltage does not drop below 3400 mV until it is ~ 93% discharged.


As an aside, it is quite difficult to convince Nissan that a weak cell requires repair. IIRC, people have showed up at dealerships with 500 mV deltas between the weak and average cell and been told all is A OK :lol:

By the way, you should review your warranty booklet. Don't some parts of the car have an 8 yr/100k warranty ?

** the actual cell voltages are ~ 4% *higher*

LeftieBiker and SageBrush, I appreciate this extra information, it has been very helpful. I will review the warranties, as you recommended.

I will leave an update once I know more.

The battery pack has an 8-year, 100,000-mile warranty against defects and a 5-year, 60,000-mile capacity warranty. My interpretation of Nissan's battery warranty is anything inside the case should be covered for 8 years or 100,000 miles unless it is general capacity loss (which is only 5 years or 60,000 miles). The rest of the EV system is covered for 5 years or 60,000 miles so that has expired. The differences between cell voltages are minimal and not causing the "no start" condition.

Gerry

Hi lavaleaf,

I'm on Oahu, have a 2012 leaf and have pretty much the same problems you seemed to have(P0AA6 code). I can clear the dtc codes via leafspy and it will drive but the ev warning light will come back on. Also can clear the codes and charge but will stop charging after a few minutes. The hv battery modules all seem to be within a pretty close range, so I don't think it's a bad module. Just wondering if you ended with a solution for your leaf.

Aloha, Aaron