Volkswagen on Wednesday revealed fixes for the European diesel cars involved in its emissions scandal, saying it would require a massive recall lasting all of 2016.

But the technical fixes proposed to European authorities for more than 8 million cars do not apply to the approximately half-million vehicles in the U.S., where regulations on the harmful pollutants emitted at high levels by the VW vehicles are more stringent.

Volkswagen spokeswoman Jeannine Ginivan said the company’s proposed remedy for vehicles in the U.S. is different. Regulators at the U.S. Environmental Protection Agency and California Air Resources Board are currently reviewing that plan before it is publicly revealed.

That it took more than two months for Volkswagen engineers to deliver a solution to make the cars compliant with emissions standards illustrates the complexity of the challenge. The company has admitted to installing cheating software on some 11 million vehicles worldwide on vehicles dating back to the 2009 model year, tricking regulators into believing the cars met clean air laws.

In Europe, where the preponderance of the vehicles involved in the scandal are located, the fix is different depending on the type of engine. German regulators have approved the fix, VW said.

For 1.6-liter engines, it requires a “flow transformer” to be affixed in front of the air mass sensor.

“This is a mesh that calms the swirled air flow in front of the air mass sensor and will thus decisively improve the measuring accuracy of the air mass sensor,” VW said in a statement. “The air mass sensor determines the current air mass throughput, which is a very important parameter for the engine management for an optimum combustion process.”

A software update is also required to fix those vehicles, which will take an hour to fix altogether. Cars with 2-liter engines will get only a software update, requiring half an hour of time in the shop. The company is still developing a fix for 1.2-liter, 3-cylinder engines and will propose that alteration later this month.

Volkswagen said it would begin fixing European cars in January and expects the process to last the entire year in Europe.

Volkswagen U.S. CEO Michael Horn testified before Congress in October that repairing all the vehicles in the U.S. could take years and require complex solutions involving a mix of hardware and software.

Volkswagen said it would also offer “appropriate replacement mobility options” for free in Europe.

Similar fixes will be applied to all VW brand vehicles involved in the scandal in Europe, including Audi, SEAT and SKODA.

Follow USA TODAY reporter Nathan Bomey on Twitter @NathanBomey.