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NHTSA Office of Defects Investigation

Preliminary Evaluation PE21-001: Front Roof Panel Detachment

  • Closed

NHTSA's Office of Defects Investigation opened Preliminary Evaluation PE21-001 on January 8, 2021 and closed it on October 14, 2021. NHTSA's investigations file lists 21 Mercedes Benz models for it and links recall 21V-197 to it.

Updated daily from NHTSA's investigations file

Key facts

NHTSA number
PE21-001 (also written PE21001)
Investigation type
Preliminary Evaluation The first stage of most defect investigations: NHTSA's Office of Defects Investigation gathers basic information about a possible safety defect, including from the manufacturer.
Status
Closed October 14, 2021
Opened
Closed
Vehicle or equipment manufacturer
Mercedes-Benz USA, LLC
Component
Structure — Body — Roof and Pillars
Recall linked by NHTSA
  • 21V-197: Roof Panel May Detach From Vehicle, reported
Vehicles and equipment
21 Mercedes Benz models, including the AMG S63 and C300

NHTSA's summary

As NHTSA's Office of Defects Investigation wrote it for Preliminary Evaluation PE21-001.

try.vin does not copy NHTSA's investigation documents; NHTSA's investigation record lists the ones NHTSA has published.

On January 8, 2021, after ongoing review with Mercedes Benz, the National Highway Traffic Safety Administration (NHTSA) Office of Defects Investigation (ODI) opened PE21-001 to assess allegations of front roof panel detachments while driving at highway speeds in certain 2015 Mercedes-Benz (Mercedes) C-Class vehicles.

The subject front roof panel is a stationary panel composed of polycarbonate and is attached to the vehicle via adhesive at the time of manufacture. The panel is found on subject vehicles equipped with panoramic sunroofs. Over time, the subject panels may exhibit cosmetic degradation leading to replacement of the panel, a procedure which entails: removal of the old panel and adhesive, site preparation, and installation of a replacement panel with new adhesive.

The consumer complaints that prompted the opening of PE21-001 all described detachments of front roof panels that had been replaced after the vehicle was put into service.

Mercedes' internal investigation identified a broader scope of affected vehicles (2014-2020 CLA, GLA, C, S, GLC, and GLE class) and found the following potential service procedure- related causes of front roof panel detachments:- Improper surface pretreatments such as the use of the wrong primer or cleaner or scoring of the surface; or - Use of the incorrect adhesive.

These conditions lead to a front roof panel bond that, even if sound at the time of repair, cannot maintain its strength over time and environmental exposure.

Mercedes updated its service and parts ordering systems to reinforce the proper use of specified kits and procedures via webinars, shop foreman meetings, and explicit reference to the risks incurred by diverging from the repair procedures. Mercedes is also furnishing parts ordering assistance, and will hold dealerships accountable for improper repairs.

ODI's analysis of the ten complaints it has received from the public (VOQ's) and MBUSA's complaint data submitted in response to the information request letter for PE21-001 identified a total of 57 non-duplicative reports alleging incidents in which the front roof panel detached from the vehicle while in motion. Included within the 57 reports are incidents where consumers state the panel detached ...and flew off into traffic.

On March 19, 2021, Mercedes notified NHTSA that it would recall subject vehicles with front roof panels known to have been replaced after the original sale of the vehicle. In total, the recall (designated as Recall 21V197) covers 15,099 vehicles that were ever registered in the United States. Based on Recall 21V197 and the remedy implemented by Mercedes, further investigation does not appear to be warranted at this time.

Accordingly, this investigation is closed.

The ODI complaints cited above can be viewed at www.nhtsa.gov under the following ODI identification numbers: 11376425, 11352686, 11351629, 11349158, 11341541, 11337594, 11324100, 11311591, 11222127, 11404183

Vehicles and equipment listed for this investigation

NHTSA's investigations file lists these vehicles and equipment for Preliminary Evaluation PE21-001. A listed model year means only that an investigation names it; it says nothing about any particular vehicle. Model years with a try.vin recall page link to that page's NHTSA investigations section.

Mercedes Benz

All Mercedes Benz recalls

What an NHTSA investigation is

NHTSA's Office of Defects Investigation (ODI) looks into possible safety defects in vehicles and equipment, often after owner complaints. An investigation usually starts as a Preliminary Evaluation, or as a Recall Query when it concerns whether an existing recall covers the right vehicles or fixes the problem, and ODI can upgrade it to a more detailed Engineering Analysis. A Defect Petition asks NHTSA to open an investigation, and Audit and Equipment Queries are administrative investigations into whether companies complied with federal vehicle safety requirements, such as reporting, recall and certification rules.

An open investigation is not a finding that a safety defect exists, and NHTSA can close one without a recall.

To see whether a specific vehicle has an open recall, enter its VIN at nhtsa.gov/recalls.

Mercedes Benz VIN check: decode a VIN to see its year, make and model.

Sources

NHTSA's investigation record for PE21-001

Investigation details come from NHTSA's investigations file, which try.vin imports once a day. The investigation types are described from the U.S. Department of Transportation Inspector General's May 2023 report on NHTSA's Office of Defects Investigation, NHTSA's petition rules (49 CFR Parts 552 and 557) and NHTSA's Office of Defects Investigation procedures. How try.vin reads NHTSA investigations.