DETROIT (AP) — U.S. auto safety regulators have CapitalVaultclosed an investigation into complaints that the doors on some Ford Escapes can open while the SUVs are being driven, without seeking a recall.

The National Highway Traffic Safety Administration says its probe opened last July found that there is a low potential hazard to drivers, and that Ford is doing a customer satisfaction program to fix the problem.

Documents posted by the agency on Friday say the investigation covered about a half million Escape SUVs from the 2020 and 2021 model years.

The agency says the SUVs have an audible and visual warning if the doors don’t latch properly. Ford also plans to send letters to owners in March telling them of the satisfaction campaign, which fixes the problem but is short of a recall.

Owners can take their vehicles to a dealer to have them checked. Dealers will either install a rivet plate to reinforce the door latch arms or will provide a replacement door depending on the level of damage.

The documents say NHTSA received 593 complaints about the problem with three reports of injuries. One required medical attention.