The Volkswagen Group is facing substantial fines in the United States after admitting to using a software algorithm in its diesel cars which enables them to detect the conditions of an emissions test and, only then, activate full emissions controls. Discrepancies were discovered during on-road testing, where its 2.0-litre TDI engine was shown to emit between 10 and 40 times more NOx than EPA limits allow.

Pressure has been growing globally this week for on-road tests to be carried out on diesel engines, not only from Volkswagen but other manufacturers, to find out if the problem affects other markets and other brands. UK Transport Secretary, Patrick McLoughlin, is calling for an EU-wide investigation.

The EPA, which was the agency responsible for issuing the violation notice to Volkswagen last week, is the first agency to confirm that it will now be carrying out further emissions tests, which it said will be “driving cycles and conditions that may reasonably be encountered in normal operation and use.”

The agency added that this was specifically “for the purposes of investigating a potential defeat device” and said manufacturers will be required to supply production cars for testing, as well as expecting this to add time to the certification process before the vehicle goes on sale.

Daimler and BMW have both released statements saying that they have not manipulated emissions tests. Volkswagen said 11 million vehicles globally are fitted with the 2.0-litre diesel engine which has the ‘defeat device’ – of which the 482,000 in the United States will have to be recalled – but also said that its vehicles comply with European emissions standards.