Battery Management System Malfunction

[KonaGav]

Hi there,

I have a 22 plate Kona EV. A couple of months ago, during a cold spell, i started the car and put the heating (including AC) on at 22°. Within 5mins, the car felt like it was way above 22, so i turned the dial down to 18°. Still roasting hot air blasted out, until i turned the heating off. Shortly afterwards, i got the warning - Battery Management System Malfunction. Visit an authorised Hyindai Dealer for Inspection.

I stopped the car, switched everything off and waited a few minutes whilst trying to find the number to call. Whilst ringing, i tried starting the car again and the warning was gone. Hyundai dealer said that if it happens again to call breakdown assistance as they would be better placed to deal with it?

Anyway, no issues since then; until this morning. Again, cold weather and same issue, only this time with a slight burning smell. Thankully, i was near the house so parked on the drive and called hyundai assistance. AA came out. The warning light was gone and nothing showing on the computer in terms of faults.

I will book it in to Hyundai, but the AA guy is telling me that they will unlikely find anything unless the light comes on during inspection.

Has anyone else had this issue? I can't find any details about it anywhere.

[KiwiME]

It's really up to the dealer to diagnose and repair this but it sounds like the cabin PTC heater has a problem.

That would cause all those symptoms, overheating, smell and warning light.

Similar complaints have been reported before but I don't believe I've seen what the resolution was.

[adeaxe]

22 year kona ev. Had the same error driving on a very cold day after about 30 minutes of driving, which, after turning the car off and on, does not reappear. Of course, I didn't take a picture of the message . Battery Management still registers as abnormal in the app vehicle report. Spoke to the local dealer - no clue what it might be and suggested it come in for a diagnostic which they can't do until the end of December. They said it was safe to carry on using it, but who knows? Fortuitously, car had already been booked in for a service (elsewhere) next week so hopefully know more then.
Interesting the possible link (?) to the cars heating. My heater is intermittent. I can set a temp and it warms up. Then goes cold and then difficult to get it to heat after that. Presumably the heater runs on the 12V battery - I'm beginning to wonder if its not being properly recharged by the battery used to propel the car. I do use the heated seats etc quite a bit in the winter.

[KiwiME]

Both the PTC (resistance) heater and heat pump (where equipped) run off the traction battery.

[Greggy]

I am in exactly the same position. BMS fault flagged by car and Amber warning plus text in console. First time it happened it wasn’t present after restart but re occurred in the cold. AA came out and found a code which they deleted. they then tested the car and sent me on the way.

Next cold spell same issue. This time the AA found the same code and recovered the car to the Hyundai local dealer.

Waiting to see what happens next. The dealer is not inspiring any confidence so far.

I will let you know what I’m told and try to upload the fault codes from the AA

[Greggy]

The code was P0AA600.

I got tired of waiting for a progress report so went into the workshop and spoke with the technicians. They had put the car on the Hyundai diagnostic and the fault codes seemed a little mis leading.

They had replicated the fault on de mist with the ac and heating on. Whilst the diagnostic system said the ac was fine they had manually tested the current that the ac system was pulling and it was apparently very off spec. They are replacing the ac system when the parts are in. We will see if that fixes the issues

[Siassier]

I’ve had something similar happen with my EV during a cold snap, where the heating went nuts and I got a warning about the battery management system. Turns out it was a software glitch that got sorted after a quick update. The burning smell sounds like it could be from the HVAC system overworking, maybe trying to keep up in the cold. The AA guy’s right—it’s hard to diagnose if the warning isn’t there, but definitely get it checked out when you can.