TORONTO — Volkswagen Canada has told dealers to stop selling diesel-powered vehicles involved in an emissions-testing scandal that has drawn the ire of American regulators. Spokesman Thomas Tetzlaff said in an email that the Canadian division of the automaker is working with its American counterpart and parent company in Germany to resolve the issue. Volkswagen CEO Martin Winterkorn apologized on Sunday following revelations last week that the company had rigged U.S. emissions tests for about 500,000 diesel cars. Tetzlaff said nearly all of the company's Volkswagen-branded diesel cars are included in the stop sale order in Canada, including the Jetta, the Golf, and the Beetle. No mention was made of what is to happen with cars already on the road. The U.S. Environmental Protection Agency said Friday that Volkswagen had programmed the computers in its vehicles to recognize emissions testing and turn on extra pollution controls that are not engaged during regular driving.