Volkswagen CEO Matthias Mueller says the company will have technical details on fixing cars fitted with emissions-rigging software to German regulators by month's end, and most will not need major work.

According to a copy of a speech he gave to company managers at Volkswagen headquarters Monday, Mueller said the Federal Motor Transport Authority has signed off on a update to fix affected 2-liter diesel motors, and has given the "basic go" to a fix for the 1.6-liter vehicles that will also involve replacing an air filter cartridge and grill. Details are being finalized on a software fix for 1.2-liter motors.

Mueller says "for about 90 percent of the group's vehicles in Europe the solutions are confirmed. The cost for the retrofitting is technically, physically and financially manageable."