VW US boss Michael Horn
Michael Horn, boss of VW Group America, said his company 'totally screwed up' over emissions test cheatingReuters

Volkswagen's US boss, Michael Horn, has admitted he knew about rigged engines after he was told about the issue as early as last year, as more American and Canadian cities launch their own investigations.

Horn is set to apologise on 8 October for the company's actions in intentionally evading meeting diesel emission requirements in America involving nearly 500,000 vehicles since 2009.

In a testimony due to be presented to a panel of investigators at the House of Representatives today, Horn confirmed he was made aware of "possible emissions non-compliance" by the company in a West Virginia University study in spring 2014. The hearing will also include testimony from the Environmental Protection Agency (EPA), which sets the emissions standards for cars in the US.

"I was informed that EPA regulations included various penalties for non-compliance with the emissions standards and that the agencies can conduct engineering tests, which could include 'defeat device' testing or analysis," Horn said. "I was also informed that the company engineers would work with the agencies to resolve the issue."

VW faces new lawsuits in US and Canada

Meanwhile across the US and Canada, more cities and provinces are launching their own investigations and filing lawsuits against the car manufacturer.

The city of Dallas in Texas announced on 7 October it is planning to follow Texan Harris County's lead in filing a lawsuit against Volkswagen, alleging that the car maker violated air quality emission standards, according to the Dallas Morning News. Last week, Harris County, which county seat is Houston, sued Volkswagen saying that 6,000 cars on local roadways had contributed to the county's poor air quality.

In Canada, meanwhile, Ontario's environment ministry has announced it is investigating Volkswagen Canada and Audi Canada, owned by Volkswagen, for selling faulty cars. The ministry says Volkswagen and Audi Canada must find an province-specific solution to the software issue, reported the Canadian Press, and is asking the company to detail whatever actions it plans to take to fix the cars sold in Ontario that do not meet emissions standards.