Unveiling the Core Issue: The failure of Hyundai Kona EV’s battery cooling system traced back to the incapacity of the control module to operate the expansion valve. This led to consequential damage to the compressor, a critical component in the cooling process.
Diagnostic Challenge: The service team initially identified the problem as a clogged expansion valve, a situation they had encountered before. Surprisingly, the real culprit was the malfunctioning control module, a discovery made after salvaging parts from their test drive vehicle to keep the afflicted vehicle running.
Protracted Resolution Process: Awaiting the arrival of the AC Control Module, the service team improvised by using salvaged parts. After three DC charging sessions, the issue was conclusively diagnosed. The protracted saga now heads towards its fourth and final round of fixing, extending the ordeal into the fifth month.
Missed Opportunities: A critical misstep in the troubleshooting process emerged when the vehicle wasn’t tested with DC charging after the first round of fixes. This omission resulted in three subsequent rounds of expansion valve and compressor replacements, escalating both inconvenience for the owner and costs for the service center.
BMS Shortcomings: Notably, Hyundai lacks a comprehensive test or check for the expansion valve or compressor, lacking fail-safes or warnings. The Battery Management System (BMS), despite being a crucial element, lacks identifiers and failsafe measures to address issues before the compressor fails.
Five-Year-Old Product, Persistent Issue: Despite being a mature product, the Hyundai Kona EV, with its NMC chemistry, still faces a known issue. The BMS updates over the five years have failed to provide fixes or preventative measures for this specific problem.
Identifiers and Warning Signs: Two rudimentary identifiers emerge – DC Fast Charge throttling at charge levels below 80%, a red flag for potential compressor issues. Additionally, a manual check of the expansion valve after DC charging provides insight into potential problems, though this comes after the fact.
This lack of proactive measures underscores the need for Hyundai to enhance BMS capabilities, preventing these issues before they lead to costly and inconvenient breakdowns.