Every vehicle sold in the US must conform to a massive amount of regulations known as the Federal Motor Vehicle Safety Standards. If an even seemingly insignificant FMVSS violation makes it to market, it's all but guaranteed that a recall will follow. That's the reason behind VW's latest recall, which is a big one.
Volkswagen has issued a recall for 662,185 examples of the 2018-2019 VW Atlas SUV and the 2012-2020 VW Passat sedan. There are a lot of cars in this recall, carrying a wide variety of build dates and non-sequential VIN ranges, so it's best to give your dealership a ring if you think your vehicle might be part of this.
The problem stems from a single cap. When it's still being assembled, factory workers align the headlights' horizontal aim, and then that aim adjuster is sealed off with a cap. However, the vehicles included in this recall never had that cap installed, allowing Average Joes and Janes to adjust the headlights horizontally. This puts the vehicle in violation of FMVSS 108, which states that headlights are not allowed to be adjusted horizontally after assembly. Since it's out of spec according to federal regulations, VW initiated a recall to remedy the issue.
VW discovered the problem in early 2019, when the automaker discovered missing instructions about installing the horizontal-aim adjustment cap. VW remedied this by correcting the work instructions, and then it went about figuring out how many vehicles had these missing caps. If a person changes their headlights' horizontal aim, it may not provide adequate coverage as expected, which could present a safety hazard.
Volkswagen is still researching a permanent remedy, but the idea behind it is simple: Dealership technicians will block the horizontal aim adjuster, preventing owners from making changes after the vehicle has been sold. Dealers have already been notified of the recall and affected owners should start to receive notifications in the mail later in July.