Complaints are mounting among owners as defects in the battery management system (BMS) of vehicles made by U.S. electric car company Tesla continue. While the number of Tesla vehicles supplied in Korea keeps increasing, service centers are limited, lengthening repair times and adding a hefty repair cost burden, critics said.
According to the industry on the 17th, some Tesla vehicles sold in Korea are experiencing battery management system (BMS) errors. A warning message reading "BMS_a079" appears on the instrument cluster, and when this error occurs, battery charging is restricted and driving range is reduced.
The BMS is a device often called the brain of an electric vehicle. It checks the battery's voltage, current, and temperature to control the system for optimal performance, and alerts users to warning signs in advance to prevent overcharging and discharging.
According to "BMS repair records" submitted by Tesla Korea to lawmaker Park Yong-gap of the Democratic Party of Korea, a member of the National Assembly's Land Infrastructure and Transport Committee, there were 4,637 BMS error-related cases over about five years from August 2020 to 4th. The number of vehicles with problems is at least more than 4,000, and the share is known to be higher for the main models Model Y and Model 3.
To resolve a BMS error, repairs such as battery replacement are required, with an average repair period of 23.4 days (overall EV average 10.7 days). For vehicles whose warranties have expired, the repair expense is known to range from several million won to more than 30 million won.
There are cases where the same vehicle experiences recurring BMS errors and undergoes multiple repairs. Over the past five years, 245 vehicles were repaired at least twice, and 19 vehicles were repaired three or more times. In an online community related to Tesla, one user said, "I replaced the battery in my 2021 Model Y once, but after the warranty ended, a second error occurred recently and the repair cost came to 28 million won."
Tesla Korea is guiding that BMS errors do not affect vehicle driving but that a maintenance appointment is necessary. It said that to minimize inconvenience to owners, it provides rental vehicles during maintenance or repair periods and has requested the headquarters for a smooth supply of batteries to shorten wait times.
Since last year, Tesla has sold lower-priced China-made "Model Y" and "Model 3," and domestic sales have been surging. According to the Korea Automobile Importers & Distributors Association (KAIDA), Tesla sales from the start of the year to 4th reached 43,612 units, up 84.7% from the same period a year earlier. The Model Y (37,035 units) beat the Mercedes-Benz E-Class (19,681 units) and the BMW 5 Series (18,206 units) to take the top spot among imported car models.