Hyundai Sonata 2018–2019 — technical service bulletin
Bulletin 21-AT-001H · NHTSA communication 10186820 · issued Jan 14, 2021
Technical service bulletin
communication type
Power Train
component
2018–2019
model years
2
vehicle entries
Official summary
This bulletin provides the procedure to update the TCU for a rough idle in Drive with Neutral Control enabled. The rough idle may occur only at a stop in Drive with the A/C off and the ATF temperature between 158~210°F (70~99°C). This update also reduces vibration when the brake is released during Neutral Control operation and the accelerator pedal is depressed.
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.