Fiat Chrysler Automobiles (FCA) has been given approval to sell its 2017 model year diesel vehicles.

The automaker has been under fire, with U.S. and California regulators alleging FCA’s older diesel vehicles had undisclosed emissions controls, allowing them to emit excess pollution in normal driving.

READ MORE: Ram Diesel Owners Suing FCA, Cummins Over Inflated Fuel Economy

FCA has refuted the claims since the beginning and now hopes the approved software fix it is using on 2017 model year vehicles can be the foundation for a fix on older 2014-2016 diesel vehicles. The company restarted production earlier this month in anticipation of approval and promises the software update will have no effect on the fuel economy ratings or vehicle performance.

FCA has been adamant that it does not fall in the same category as Volkswagen, and never created software to cheat emissions rules. Both the U.S. Environmental Protection Agency (EPA) and the California Air Resources Board (CARB) has accused FCA of using the undisclosed software in 104,000Jeep Grand Cherokees and Ram 1500 trucks in the U.S. from model years 2014 to 2016.

This article originally appeared on AutoGuide.com