My 2020 Kona Electric Limited with 58,274 miles displayed the Check Electric Vehicle System (CEVS) dashboard warning on July 18, 2023. I purchased my Hyundai used CPO from a dealer in Southern California in January, and it still has the CPO warranty in effect until 60,000 miles. Like others in this CEVS thread, my gear options were park or neutral, but not reverse or drive. I replaced the 12v battery but there was no change in the CEVS dashboard warning or vehicle operation. Since there was no change, I returned the new 12v battery.
My local dealer in Roseville, California had no service appointments available for 3 months. Folsom and Elk Grove were similarly backed up. Stockton, 50 miles away, could take me the next day. I spoke to Hyundai customer care and they confirmed that Hyundai roadside assistance would tow my vehicle to a dealer within 30 miles. If I wanted it towed to Stockton I could pay the difference for the additional 20 miles. I decided to upgrade my AAA membership from basic (5 mile tow) to plus (100 mile tow) and waiting 10 days for the upgraded towing benefit to take effect.
On July 31, I had my vehicle towed by AAA to Stockton Hyundai on July 31. August 1, no update. On August 2 they asked me for and received my authorization to replace the 12v battery, and applied and road tested a battery management system update. My vehicle was fixed and ready for pickup later that day. While the vehicle was there they also flushed and replaced the inverter coolant (TSB 23-01-049H). I was also told by the service advisor that if the vehicle exhibits the same CEVS problem/diagnostic code, I should expect to need to replace the high voltage battery. Note the reference to TSB 21-01-006H in the paperwork notes below. The car has worked fine since.
Relevant TSB Links
Relevant Paperwork Notes
A CUSTOMER STATES THAT CHECK ELECTRICAL SYSTEM IN VEHICLE LIGHT IS ON AND VEHICLE WILL NOT GO INTO REVERSE OR DRIVE CHECK AND ADVISE
CAUSE:
100 CUSTOMER STATES THAT CHECK ELECTRICAL SYSTEM IN VEHICLE LIGHT IS ON AND VEHICLE WILL NOT GO INTO REVERSE OR DRIVE CHECK AND ADVISE 80380 W (N/C)
VERIFIED CUSTOMER CONCERN
CHECK VEHICLE VOLTAGE SYSTEM MESSAGE DISPLAYED ON CLUSTER
CONNECTED GDS AND RETRIEVED CODES
P1AA600 HYBRID/V BATTERY ABNORMAL PERFORMANCE DETECTION
P0AA700 HYBRID /EV BATTERY VOLTAGE ISOLATION SENSOR CIRCUIT
B111216 BATTER VOLTAGE LOW
C182C00 EVSE FAILURE
FOUND OLD CAMPAIGN PREVIOUSLY DONE TO VEHICLE THAT APPLIES TO DETECT DIAGNOSTIC CODE
TSB 21-01-006H
OPEN TECHLINE 2023080102114
CONTACTED TECHLINE
ADVISE TO RECOVER FREEZE FRAME DATA OF CODES P1AA600, P0AA700, AND CURRENT BMS DATA
UPON SECOND CONNECTION OF SCANNER CODE P0AA700 HAS SELF CLEAR AND DID NOT SHOW UP ON CODE SCAN, UNABLE TO RECOVER FREEZE FRAME FOR P0AA700
SUCCESSFULLY RECOVERED FREEZE FRAME OF PIAA600 AND CURRENT BMS DATA, TRANSFERRED TO TECHLINE VIA STUI
CONTACTED TECHLINE AGAIN
ADVISE TO PERFORMED REVISED BMS UPDATE
PERFORMED UPDATE FOR BMS
CLEAR CODES SET BY UPDATE
ROAD TEST VEHICLE
NO CODES ON ROAD TEST
CUSTOMER CONCERN REPAIRED