I’ve driven my 2024 Hyundai Sonata for about 10,000 miles and have documented the speedometer discrepancies, reporting them to Hyundai Service Teams three times. In my view, this makes the car a lemon.
Hyundai either needs to fix the issue or buy back all affected vehicles. If you drive at a posted “MINIMUM” speed limit and the speedometer shows the “posted Minimum Speed Limit” while you’re actually traveling slower, you could be cited for driving too slowly and impeding traffic.
A Hyundai Service Manager suggested the problem might be due to satellite signal delays, but this doesn’t explain the inconsistencies. The issue seems to be with the car itself, not external devices. I urge everyone with similar issues to report them to the National Highway Traffic Safety Administration (NHTSA). Hyundai needs to address this problem or consider the cars as lemons. For those experiencing issues, a workaround involves stopping the car, turning off the engine, and opening the driver’s door to reset the speedometer’s accuracy temporarily.
My 2021 Sonata generally matches Waze readings, with only minor discrepancies of about 1 mph when accelerating or decelerating. It’s normal for some speedometers to be slightly inaccurate—only police speedometers are certified for precision. Being off by 1 or 2 mph won’t lead to a ticket, and it doesn’t mean your car is a lemon. There are people with real car issues, and this isn’t one of them.
My 2006 BMW consistently showed 5 mph faster than my actual speed on the freeway, but I never received a speeding ticket in the 10 years I owned it. My 2023 Sonata appears to track more accurately at highway speeds. If it’s off by 1-3 mph, it’s not a big deal. The original poster should reassess their priorities.
I notice speed differences when accelerating or decelerating, but it stays consistent with cruise control. I’m assuming GPS takes time to calibrate speed, which is normal.
I don’t usually track speedometer errors, but I noticed my 2011 Sonata had an average odometer error of about -3%, which seems similar on my 2018 model. This can be advantageous for warranty purposes. I traded my 2011 with 88,000 miles on the odometer, estimating the actual mileage at around 90,650. Various factors, like tire circumference and differences between road and GPS readings, can affect odometer and speedometer accuracy. As someone who worked as an aviation psychologist for 30 years, I understand that all measurements include both true variance and error variance, and the standard error of estimate is never zero.
