Marchionne replaced Luca di Montezemolo as the head of the Italian constructor in October and hopes changes made to the team can see them become competitive next year.
Ferrari failed to win a single race in 2014 and only made the podium on two occasions as they struggled with pace and reliability, eventually finishing a massive 485 points behind constructors' champions Mercedes.
As the new season looms on the horizon, Marchionne is determined to oversee a change in fortunes.
"We must forget 2014, I don't want to talk about 2014," he said. "We have made many mistakes.
"We had a lot of unexpressed potential in 2014, so the big challenge is that in 2015 Ferrari will start to show the reconstruction of the whole team."
However, Marchionne has warned that Ferrari should be prepared for a transitional season after delays with the design of their new car.
He added: "We started late with the 2015 car, certain choices and strategies that were made by others and that, in retrospect, I don't necessarily share.
"So 2015 will be a difficult year that will put the team to a real test. I think 2015 is going to be a reconstitution year.
"I think Ferrari can probably get to the same place [as Mercedes] by the end of 2015. Some of the work has already started. We need to be able to emulate their success."
Ferrari have already made some changes ahead of 2015, with four-time world champion Sebastian Vettel taking the seat of Fernando Alonso, while engineering director Pat Fry has been replaced by Mercedes performance engineer Jock Clear.