text: Speaking at the Consumer Electronics Show (CES), Herbert Diess, head of the VW brand, said the company would have a fix in the coming weeks or months.
  But the US Environmental Protection Agency (EPA) was less certain, saying that Volkswagen "have not produced an acceptable way forward".
  The EPA disclosed VW's use of "defeat devices" in diesel cars in September.
  The devices disguised diesel cars' emissions levels that were, in fact, up to 40 times above the US legal limit.
  The EPA has insisted that the German carmaker comes up with a solution that will not cost money for VW owners.
  Mr Diess told the CES show, in Las Vegas: "I'm optimistic that we will find a solution. We will bring a package together which satisfies our customers first and foremost and then also the regulators."
  Mr Diess said Volkswagen has reached an agreement with European regulators to fix 8.5 million cars affected there.
  On Monday, the US Justice Department filed a lawsuit against VW for the use of the emissions devices, which involve computer software that can detect when cars are being tested.
  The company and its executives could still face separate criminal charges, while a raft of private class-action lawsuits filed by angry VW owners are pending.
target: Embattled carmaker Volkswagen said it is close to an approved fix for US cars with emissions-deceiving devices.