How Hyundai finally diagnosed & fixed my Kona's battery cooling issue

Even the service personnel told me that this was the first time that they had faced another iteration of this flaw in the Hyundai Kona EV.

BHPian EV Fan recently shared this with other enthusiasts.

Final update after adequate self-testing & a scheduled service – Fully operational vehicle, especially thanks to the outreach that Team-BHP as a forum gave me.

And certainly the folks at Popular Hyundai dealership at Kochi and their Hyundai counterparts, who actually fixed it albeit with a bit of nudge.

They have finally fixed the root cause which was causing the compressor to fail repeatedly - The AC Control Module, which basically manages the entire cooling operation, was unable to operate the expansion valve (EXV). Without the expansion valve opening, the compressor was getting damaged every time.

The service team at Popular Hyundai dealership, ended up misdiagnosing it, as their fault identification stopped at the expansion valve, based on their prior experience with a few Konas.

But this time along with the Hyundai tech support they compared diagnostic datasets during charging, from my vehicle and compared it with a perfectly working vehicle. This helped them to identify that the AC control module was unable to provide the input signal, to open the Expansion Valve.

While this helped them identify and fix the issue – it did highlight to me the critical flaw in the Kona’s cooling circuit (and not something new either, quite a few Kona owners in India have already faced it).

Unlike other EVs which use a single AC circuit for both cabin AC & battery cooling, Hyundai tried giving separate cooling circuits for cabin and battery cooling in the Kona.

The flaw in this design is that the customer will not be aware when this fault occurs, as the cabin AC works perfectly, till the time we do the DC Fast charging (DCFC-50KW or higher) without cabin AC. During the DCFC, if the Expansion valve (Battery Cooling) does not open, the pressure builds up in the compressor. Result - The compressor fails as the alternate path for the cabin AC is also closed.

Now this usually used to happen in Konas when no DC FC was done in a long time and the lack of operation of the battery cooling circuit, used to jam up the expansion valve. The EXV replacement was used to fix this but not so in this case, so as per the service personnel, this is the first time they faced another iteration of this flaw. They never knew it could even happen due to a failed AC control module.

So unless Hyundai figures out, how to identify if the expansion valve is operational or prevents pressure build up at the compressor, the dealerships can only do post failure – repair, for the compressor and the expansion valve.

Even a Self-Test, whereby the Battery cooling circuit is operated/tested during charging or on periodic intervals, would be a solution better than nothing. Something similar in lines to what they had already provided for the 12V battery discharge issue.

Anyways, with the fault isolated, they tested my vehicle with a replacement AC control module from their Test Drive (TD) vehicle. And more importantly, they ensured to do proper testing with DCFC before confirming the resolution to me.

Thankfully instead of waiting for the replacement part to arrive, they gave back the vehicle with the borrowed part from their TD vehicle. While it might be a small gesture for them, for me it was a major relief as I finally had a proper operational vehicle after a “few months”. I hope that dealerships can understand how these gestures can go a long way to ease the misery in such a scenario.

Finally, to make amends, they also gave my vehicle a “top to bottom” shine.

And the cherry on the cake, the entire round trip had the best efficiency figure the Kona has given up to date. 13.38 KM/KWh or 74.75Wh/km over 215 kms (heavy traffic city+highway drive). I guess the new compressor and the service did work their way to the numbers.

The 80 to 75% difference was when the service guys were working on it (I am not posting the blasphemous value).

So, did the shine and the brilliant efficiency make me forget about all the hassles? Almost a yes, until they somehow managed a minor goof-up in the end even this time. Yes, they have a packed-up schedule and tight working space, but I don’t think it is still wrong to expect a niggle free experience.

But honestly, I am thankful to the folks at Popular Kochi, especially Vikas & Hari, who stepped up the effort towards a more customer-centric experience. Their efforts and the Kona’s efficiency, just made me consider holding on to it rather than jumping on the bandwagon of the competitor for now.

The strict convention of regular DC charges of 50KW or above, at least once a month or higher, still holds. (Even though I would mostly not need it thanks to the range it gives).

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