Engineering Analysis EA14-002: Panoramic Glass Sunroof Breakage

The investigation focused on spontaneous breakage (fracture) of the panoramic sunroof (sunroof) on MY 2011-2013 Kia Sorento vehicles. The sunroof is constructed of tempered glass (often referred to as ?safety glass?), which, when broken, crumbles into granular chunks rather than splintering into jagged shards. The failure summary above shows NHTSA reports identified by the Office of Defects Investigation (ODI), and reports submitted by Kia from start of production of the subject MY 2011-2013 Kia Sorento through October 8, 2019, the date of ODI's last request for Kia data.

Reports of sunroof failures typically occurred while the vehicle was in motion and often described a loud noise when the fracture occurred. If the sunshade is closed when the sunroof fractures, the particles are contained, otherwise the particles can drop into the passenger compartment.

Reported injuries generally were minor in nature, such as nicks and cuts that often occurred when complainants were cleaning-up glass particles post-incident. No crash incidents have been identified, and complaints display a declining trend since 2014.

During EA14-002, ODI requested and obtained failure data for the subject vehicles, the MY 2014 Sorento (which used a similar sunroof from a different supplier), and other peer Kia products (Optima and Sportage).

ODI also requested and obtained failure data for peer vehicles produced by Hyundai, Ford, Nissan, and Volkswagen and failure reports through a General Order NHTSA issued to 13 OEMs (including Kia) in April 2016.

This produced a significant volume of data upon which ODI bases this closing. NHTSA's Vehicle Research and Test Center (VRTC) also conducted testing on the subject sunroofs in an attempt to better understand potential hazards.

In its responses to ODI, Kia states it has continuously monitored sunroof failure allegations throughout this investigation, and that the only consistently identified cause is external impact from foreign objects. Kia notes that the sunroof complies with the applicable Federal Motor Vehicle Safety Standards for glazing, and that it has not identified a manufacturing defect or assembly process error despite significant investigative efforts. Kia maintains that the field data supports its conclusion that an unreasonable risk to motor vehicle safety does not exist, citing a comparatively moderate failure rate, low injury risk posed by tempered glass, and the lack of an identified defect mechanism. Kia further notes it has received no reports of crashes due to driver distraction related to roof failure events, nor is NHTSA aware of any such reports.

NHTSA's April 2016 General Order requested data on vehicles with panoramic glass sunroofs greater than 0.5 square meters in area. The response identified 97 distinct models produced over 11 model years totaling some 10 million vehicles. Over 4,000 sunroof fractures were reported (none of which alleged a crash due to driver distraction) forming a high to low frequency continuum by model.

While the subject vehicles were at the high end of the spectrum, they were not the highest.

Through its analysis of the information obtained to date, ODI has not identified sufficient evidence of a safety-related defect in the subject sunroof. This includes the absence of any suggestive trends by region, seasonality, date of production, or vehicle age, together with the minor nature of the alleged injuries and the lack of crash allegations in the subject or any of the peer vehicles. Accordingly, the investigation is closed. ODI will take further actions if warranted by new evidence. The reference numbers for the ODI failure reports cited above, as well as additi