US authorities probe Bosch's role in rigging

US authorities are investigating German auto supplier Robert Bosch over its role in Volkswagen AG's massive scheme to cheat US emission standards, according to people familiar with the matter.

Federal prosecutors with the US Department of Justice are examining whether Bosch, the world's largest auto supplier, knew or participated in Volkswagen's years-long efforts to circumvent US diesel emissions tests, the people said. Bosch built key components in the diesel engine used in six Volkswagen models and one Audi model that the automaker has admitted to rigging to defeat emissions tests. Federal authorities are also investigating how deeply the scheme permeated Volkswagen's hierarchy, according to people familiar with the matter.

The probe is at an early stage and there is no indication that US prosecutors have found evidence of wrongdoing at Bosch, the people added, asking not to be named because the matter is not public.

Volkswagen has admitted to installing software that allowed its 2.0 liter diesel models to pass US clean air tests, while shutting off emissions control systems when its diesel cars are actually on the road. Volkswagen said in September that around 11 million diesel powered cars were affected worldwide, including 482,000 in the United States. A Bosch spokeswoman declined to comment. A Department of Justice spokesman also declined to comment. Bosch provides the engine control module, called EDC17, and basic software for nearly all the four-cylinder diesel cars sold in North America.