Mercedes-Benz is learning a hard lesson about the importance of reliable car emergency systems. As Car and Driver and The Verge report, Mercedes USA is recalling nearly 1.3 million 2016 to 2021 model year vehicles due to a flaw n the eCall emergency calling platform. A glitch in the software might “fail to communicate” the right car’s location to first responders if the power supply drops during a crash, delaying a rescue at a critical moment.

The issue affects a wide range of Mercedes’ lineup, ranging from entry-level cars like the A-Class through to flagships like the S-Class. The company has investigated a number of incidents where cars sent the wrong locations, including a European case in 2019.

The automaker will start the formal recall on April 6th and plans to fix the issue through either over-the-air updates (via Mercedes Me subscriptions) or by having owners visit dealerships.

On top of highlighting the technical challenges of emergency calling systems, the recall illustrates the rising importance of over-the-air updates for cars. Some Mercedes owners won’t have to leave home to get a potentially life-saving fix — that could offer piece of mind, not to mention free mechanics to work on other repairs.