The circumstances under which a vehicle’s sunroof is legally allowed to close are at the heart of Mercedes’ latest recall. The unusual campaign involves a grand total of eight GLS 580s from the 2020 model year with an overeager “car wash mode.”
The problem stems from a genuine mistake that was discovered by the automaker in 2019, when the vehicles in question were being produced. At that time, the automaker found a deviation in its software-development process.
The error meant that, in addition to the other preparations that the car wash mode initiated, it also closed the sunroof. Mercedes said in documents submitted to the National Highway Traffic Safety Administration (NHTSA) that this was “inconsistent with the design intent” of the feature.
As a result, it rewrote the car wash mode code, and updated its vehicles. However, a month later, it discovered that a small handful of GLS 580s had left the factory with the old software. Nevertheless, it reports that it didn’t think this was a big problem, and you can kind of see why.
Mercedes says that it investigated the issue, and determined that there was no safety risk to owners because the sunroof has an automatic reverse mode if it senses something in its path. It added that, since the car wash mode is hidden away, deep in an infotainment menu, the chances of a driver inadvertently closing the sunroof were low.
However, its legal compliance team did note that the SUV could run afoul of U.S. regulation because of the closing sunroof. It still didn’t think that the issue was a concern, so it asked NHTSA not to be required to conduct a recall campaign with a request for “inconsequential treatment.”
On October 25, the regulator officially denied the request, so Mercedes is now launching a recall. It will start reaching out to owners on December 31, and will ask them to return their vehicle to a nearby dealer, where a technician will install the updated car wash mode code.