The contact owns a 2023 Hyundai Sonata. The contact stated while driving at various speeds, there was a loud sound coming from the rear end underneath the floorboard like a part slamming on the undercarriage of the vehicle. The contact stated that the fuel gauge suddenly indicated that the fuel tank was EMPTY. The vehicle was taken to the dealer who diagnosed that the gas valve and electronic control unit (ECU) had failed. The contact stated that the gas valve was replaced, and the electronic control unit (ECU) was updated. After receiving the repair, the contact noticed that while attempting to accelerate, the vehicle downshifted before shifting to the desired gear and accelerating. The failure was most persistent while driving uphill. The check engine warning light was illuminated. The vehicle was taken to another dealer, All Star Hyundai (3950 Century Ct, Pittsburg, CA 94565) who was unable to diagnose the vehicle due to not having the tool necessary to detach the fuel tank. The vehicle was then taken to another dealer, San Leandro Hyundai a Carnamic Car Center (1066 Marina Blvd, San Leandro, CA 94577) who diagnosed that the pressure valve was swollen and the entire fuel tank and pressure valve needed to be replaced. The vehicle was not repaired. Due to the inconsistency of diagnostic results, the contact decided to take the vehicle to another dealer, Fremont Hyundai (43690 Auto Mall Cir, Fremont, CA 94538) who diagnosed that the pressure valve was swollen but had not diagnosed that the fuel tank needed to be replaced due to not finding a failure with the fuel tank. The manufacturer was not made aware of the failure. The failure mileage was approximately failure mileage was 75,000.

- Berkeley, CA, USA