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Service bulletin LI77.21-P-080503

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id11031554
Published by NHTSA2026-04-25
Manufacturer's numberLI77.21-P-080503
Manufacturer's date2026-04-24
NHTSA componentVISIBILITY/WIPER

NHTSA's 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.” • Complete the questionnaire together with the customer. • Open a TIPS case and attach the completed questionnaire. • Submit the TIPS case to the Body / Chassis / Entertainment inbox. Repair: Perform Initial Start‑Up of the panoramic roof control unit (PSD – A98 / TSSR254).

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Glass, wipers and mirrors, Wipers and washers

Vehicles listed
MERCEDES-BENZ AMG GLC432024
MERCEDES-BENZ AMG GLC43 4MATIC2024 to 2026
MERCEDES-BENZ AMG GLC43 4MATIC COUPE2024 to 2025
MERCEDES-BENZ AMG GLC63 S E2024 to 2025
MERCEDES-BENZ AMG GLC63 S E 4MATIC+2025 to 2026
MERCEDES-BENZ AMG GLC63 S E 4MATIC+ COUPE2025 to 2026
MERCEDES-BENZ GLC 3002023 to 2026
MERCEDES-BENZ GLC 300 4MATIC2023 to 2026
MERCEDES-BENZ GLC 300 4MATIC COUPE2024 to 2026
MERCEDES-BENZ GLC 300 COUPE2024
MERCEDES-BENZ GLC 350 E 4MATIC2025 to 2026
MERCEDES-BENZ GLC43 4MATIC COUPE2026

Listing a model year does not mean every vehicle of it is concerned: the document says which.