Mercedes-Benz AMG C43 2021–2026 — technical service bulletin

Bulletin LI91.29-P-080554 · NHTSA communication 11032704 · issued May 15, 2026

Technical service bulletin

communication type

Seats

component

2021–2026

model years

vehicle entries

Official summary

Complaint One or more seat functions are restricted or inoperative. This may include: • Seat memory • Automatic seat adjustment • Easy Entry/Exit • Head restraint presetting • Collision avoidance with bench seat at rear • Actuation by other vehicle systems Seat normalization is missing, and fault code B228678 – “The control unit calibration has been lost or was not performed. Adaptation or adjustment is not correct.” is stored in the seat control unit. Additional fault codes may also be present. Cause The condition is currently under investigation. Remedy Process any additional faults first. •

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.