The panoramic sliding sunroof operates in a stepped movement
Mercedes-Benz technical service bulletin LI77.21-P-080503 for 2020-2026 Mercedes-Benz GLC 300, 2024 Mercedes-Benz AMG Glc43 and 2023-2026 Mercedes-Benz GLC 300 4matic and others.
- Bulletin number
- LI77.21-P-080503
- Component
- Electrical system
- 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. In combination with one, serval, or all of the following Fault Codes stored in the panoramic roof control unit (PSD, A98, TSSR254): • B184954 • B184955 • B1E7554 • B1E7555 Note: Please see LI77.21-P-075807 for complaints of the sliding sunroof panel of panoramic sliding sunroof reverses (temporarily, once, multiple times) during closing process without an entrapment event 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).
Owners of these vehicles have filed 95 complaints in the electrical category.
Vehicles covered
- Mercedes-Benz GLC 300 2020-2026 2020202120222023202420252026
- Mercedes-Benz AMG Glc43 2024 2024
- Mercedes-Benz GLC 300 4matic 2023-2026 2023202420252026
- Mercedes-Benz GLC 350 E 4matic 2025-2026 20252026
- Mercedes-Benz AMG Glc43 4matic Coupe 2024-2025 20242025
- Mercedes-Benz AMG Glc43 4matic 2024-2026 202420252026
- Mercedes-Benz AMG Glc63 S E 2024-2025 20242025
- Mercedes-Benz GLC 300 4matic Coupe 2024-2026 202420252026
- Mercedes-Benz AMG Glc63 S E 4matic+ 2025-2026 20252026
- Mercedes-Benz AMG Glc63 S E 4matic+ Coupe 2025-2026 20252026
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