Volkswagen is racing against time to deliver thousands of different recall solutions to its emissions-cheating crisis.

Freshly installed chief executive Matthias Müller has admitted that the complexities of operating in more than 100 markets around the world with three engine capacities and six transmissions has made fixing the troubled EA189 motors far harder than a simple software reflash.

“Volkswagen requires not just three solutions, but rather thousands,” Müller said.

That hasn’t stopped the firm from insisting it will recall the first of the 11 million affected cars from January next year and hopes to have the clean-up work finished by the end of 2016. Yet even this wasn’t voluntary, with Volkswagen being forced into delivering an enforceable timetable by the German Transport Department’s October 6th deadline.

While the cheat code - which switched the EA189 diesel motors into their cleanest settings only when it was being tested in a laboratory - is not difficult to remove, it’s buried deep inside the Bosch EDC 16 engine management software. Removing it could work for some models to help them meet NOx emissions legislation around the world, but other models will need additional software work as well.

Volkswagen sources have added detail to Müller's complexity claims, saying that besides being fitted to cars from Audi, Seat, Skoda and Volkswagen across the years from 2009 to 2013, the affected engines came in three different capacities with three different manual gearboxes and three different dual-clutch transmissions. The engines were also sold with a wide range of power and torque outputs and the cars were usually updated at least once a year.

Roughly 3.6 million models in Europe with 1.6-litre engines will require hardware changes in the wake of the company’s diesel emissions rigging scandal, a spokesman for the German transport ministry said on Friday.

“We are working through these issues as quickly as we can, but bear in mind we have to validate and check and recheck everything to avoid any deviations,” a spokesman said on Friday.

“That’s why there is not yet a definitive solution to how the recalls will be implemented and what we need to do for each car.”

Volkswagen (or some level of management at Volkswagen) introduced the “defeat” code on the EA189 when it became clear that the motors would not meet the US emissions laws, which dropped 90 per cent to 70 milligrams of NOx/km in 2009. The EU5 laws at the time had a limit of 180 mg/km.