The EPA still hasn't certified Ram's 2018 diesel trucks.

The diesel-powered Ram 1500 is finally returning to dealer lots after a nearly year-long hiatus. The truck manufacturer stopped distributing the model late last year when the Environmental Protection Agency (EPA) accused it of using an illegal defeat device.

EPA officials were alarmed by several lines of code buried deep in the 1500 EcoDiesel's engine control software. They came to the conclusion that Ram used a defeat device like the one Volkswagen fitted to millions of its cars, but they didn't uncover enough evidence to prove the allegations. The EPA was forced to drop its case and allow Ram to sell the diesel-powered 1500, which is the most fuel-efficient model in it segment.

Ram parent company Fiat Chrysler Automobiles (FCA) isn't off scot-free, according to industry trade journal Automotive News. The company is cooperating with the EPA and the California Air Resources Board (CARB), and it believes it "has developed updated emissions software calibration that [...] address the concerns of EPA and CARB."

The EPA's decision applies to the Ram 1500 and the Jeep Grand Cherokee, which uses the same engine as its pickup sibling. But while that sounds like good news for diesel fans, the celebration may be a short one. A spokeswoman for the EPA told Automotive News the 1500 and the Grand Cherokee haven't been certified for the 2018 model year yet.