The Office of Fair Trading (OFT) has launched a study into new car warranties.
The study of the £1 billion-a-year industry will examine whether manufacturers' networks are barring competition from independent warranty providers - including insurance providers.
The inquiry follows complaints that the current set-up restricts competition because owners are pressured into having warranty work undertaken at the garage where they bought their cars.
The OFT will also examine the extent to which non-network garages are prevented from servicing new cars.
John Vickers, the OFT's chairman, said: "Our study will look at how the car servicing market is affected by the warranties offered with new cars, particularly when servicing is tied to a franchised network."
The study is expected to be concluded later this year and could lead to further investigations and the involvement of the Competition Commission.
ABI spokesman Malcolm Tarling said: "The ABI will be pleased to work with the OFT on this investigation."
