NHTSA Complaint #11498342 — 2017 HYUNDAI SONATA

2017 Hyundai Sonata with Theta II engine received knock sensor detection software update 7/30/19. Engine knock increased substantially during August and September of 2022 with periodic, partial loss of power at idling and significant oil consumption. Dealership initiated oil consumption testing 9/24/22. On 11/2/22, vehicle fully stalled with blue smoke from exhaust during slow-speed turn in normal driving conditions. Owner and child in vehicle were uninjured. Dealership unable to replicate stall or identify error codes. Dealership's 11/11/22 oil consumption test identified excessive oil consumption. Dealership cleaned combustion chamber. Vehicle experienced partial stall 12/15/22 at moderate speed in normal driving conditions. Dealership performed final oil consumption test 12/20/22 and reported normal oil consumption (.25 quart in 1,000 miles).