The contact owns a 2021 Chevrolet Silverado 1500. The contact stated that while driving at approximately 35 MPH, the engine started to misfire. There was an unknown service warning light illuminated. The vehicle was taken to the local dealer, where it was diagnosed that left side valve lifters needed to be replaced. The codes displayed were 0329 (Engine/Fuel Exhaust) and 6581 (Modular Component) registering incorrectly. The vehicle was repaired. The manufacturer was not contacted. The failure mileage was approximately 15,253.