(FORTUNE Small Business) – If your new car breaks, you can just take it to your favorite mechanic, right? Not necessarily. Independent mechanics complain that automakers withhold technical data needed to fix increasingly computerized cars. Earlier this year Erminio Caporale, owner of P&E Service in Morton Grove, Ill., replaced the engine computer in a customer's Ford van, only to find that the local Ford dealer wouldn't release the information to program it. Caporale had to tow the van to the dealership and pay $150 for programming. This fall Congress is expected to take up the Motor Vehicle Owner's Right to Repair Act, which would mandate the flow of information to the indie shops. "How many times can I tell a customer, 'Take it to the dealer,' before I lose the customer?" asks Caporale. Ford replies that it is already in compliance with the act. --I.M.