Volkswagen recently announced that it is developing a fix to put 11 million cars back into emissions compliance, but analysts believe the solution will be more expensive and challenging than Volkswagen’s assessments.

“We have a long road and a lot of work ahead of us,” said newly appointed Volkswagen Group CEO Matthias Müller on Monday. “To this end, thoroughness is more important than speed.”

Volkswagen anticipates it will begin fixing the affected vehicles as soon as October, according to Bloomberg Business, and experts are still not sure how this will be completed.

“My theory is that due to the sheer competitiveness of the U.S. market, VW undersized the LNT to get better fuel economy,” said Nick Molden, founder and CEO of Emissions Analytics, a firm that conducts fuel efficiency and emissions tests. The LNT he refers to trap nitrous oxide emissions, and will likely be part of Volkswagen’s solution.

“I suspect there will be some sort of hardware intervention,” Molden said.

SEE ALSO: Why Volkswagen Resorted To Emissions Cheating

That means Volkswagen needs to design, produce and install this new component, all for the $664 per car that the company has set aside to handle the problem.

As if this task wasn’t complicated enough, in order for Volkswagen to simultaneously retain as much of its reputation as possible, the company’s solution must hit a trifecta for consumers:

  • The update can’t significantly reduce the car’s fuel economy or performance. As noted by Automotive News, “A reduction of either would likely trigger even more class-action lawsuits from disgruntled Volkswagen owners.”
  • The emissions fix must integrate into the car relatively easily without altering the car in a way that decreases either its value or its safety rating.
  • The fix must come quickly.

A calibration expert that spoke anonymously with Automotive News also agreed that the repair will be costly, and could potentially affect fuel economy.

“It is difficult to imagine that the software could be updated to always meet emissions without impacting fuel economy or emissions, or the defeat device would not have been used from the beginning,” noted the expert.