BBC: Shares in VW have dropped after it reported "irregularities" in carbon dioxide emissions levels, which could affect about 800,000 cars in Europe.
An internal investigation by the firm into diesel emissions revealed that CO2 emissions and fuel consumption were understated during standards tests.
VW said it concerned mainly diesel but also some petrol models and could affect VW, Skoda, Audi and Seat cars.
It comes weeks after VW was accused of cheating nitrogen oxide level tests.
Cars with...