Volkswagen has developed fixes for vehicles implicated in the ongoing emissions-test-rigging scandal, according to a report in the Wall Street Journal. The company said it will submit technical details to relevant authorities in October. The Journal quotes Christian Buhlmann, Volkswagen’s spokesman for technical issues, as calling the fix “…the biggest service action in the company’s history.”

The fix will involve a software update, and some vehicles will require a hardware update as well. CO₂ emissions and fuel consumption are expected to rise “minimally” as a result of the software update, the Journal reports.

Reuters reports that VW’s new CEO told a closed-door meeting of managers, “We are facing a long trudge and a lot of hard work. We will only be able to make progress in steps and there will be setbacks.”