Mercedes-Benz AMG GLC43 2023–2026 — technical service bulletin

Bulletin LI77.21-P-080503 · NHTSA communication 11031554 · issued Apr 24, 2026

Technical service bulletin

communication type

Visibility/wiper

component

2023–2026

model years

vehicle entries

Official summary

Complaint The panoramic sliding sunroof operates in a stepped movement. The panoramic roof becomes denormalized without an apparent reason (not directly after control unit replacement). Automatic operation of the glass panel and roller sunblind is not possible; only tip‑mode operation is available. Cause Resetting the panoramic roof control unit (PSD – A98 / TSSR254) can lead to loss of normalization. The root cause for the control unit reset is currently under investigation. Remedy Contribution to cause analysis: • Print the attached document “Panoramic Roof Customer Questionnaire.” • Complet

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.