A lot of technology goes into the design and construction of modern headlights and according to a new recall, some of that technology isn’t functioning properly in the headlight assemblies of some 188,397 Subaru Imprezas. The recall affects cars built from September 2016 through August of 2019 and will require Subaru to replace the headlight assemblies with corrected ones.

Back in July of 2019, the NHTSA informed Subaru that it had found an issue with the front left halogen headlight assembly on the Impreza. At that time, Subaru almost immediately replaced a mold insert of the side reflex reflector and increased component inspection frequency.

Just a couple of months later, the NHTSA found that a damaged mold used for the side reflex reflector and a worn mold for the halogen low beam reflector had caused a change in product performance. Subaru traced the potentially affected assemblies to the production period mentioned above. They also filed a Petition of Decision of Inconsequential Noncompliance in an effort to avoid having to issue a recall.

Read More: Ford Recalls 58,000 F-150s As Their Driveshaft Could Fracture

As is obvious now, the NHTSA denied that request and will now require Subaru to replace all affected assemblies in the process. Interestingly, the same halogen headlight assembly received only a “Marginal” score from the IIHS during testing. Just like in this recall, those scores only applied to Imprezas with halogen headlights so if you have LED reflectors in your Impreza you’re off the hook here.

The institute specifically called out poor performance from the left halogen headlight during turn testing by saying “visibility was fair on both right curves and inadequate on both left curves.” In fact, technical measurements from the testing may also be an indication of the malformed headlight assembly.

In straightaway edge testing the average minimal useful illumination distance for the right headlight was 76.9 meters (84 yards) while the left headlight lagged behind to just 50.1 meters (54 yards). In fact, all low beam tests showed at least a 10 percent decrease in illumination distance for the left headlight compared to the right.

Subaru should’ve informed dealers by August 16th and plans to have all affected owners notified by October 11th. If you think your vehicle might be included in the recall you can contact the NHTSA, Subaru USA, or your local dealer to get confirmation.