About one of every 25 previously damaged vehicles have phony or dummy airbags, but only a handful of states have laws regulating airbag system replacements.

"Airbag systems are expensive to replace so to keep costs down and profits up, scam artists may cut corners," said Larry Gamache, communications director at Carfax, which is offering free airbagchecks in November.

"Victims of airbag fraud have found their airbags stuffed with everything from rags to old shoes or nothing at all. However, most victims of airbag fraud may never know until it's too late."

Airbag fraud is virtually undetectable unless you check the car's computer system.

"If these airbags have been tampered with by improper repair the consumer is buying a vehicle that is not going to offer them any safety at all," said Bruce Strain, an expert in airbag replacement.

Carfax and its affiliated dealers are offering consumers free airbag checks and Carfax Vehicle History Reports during the month of November. To locate a Carfax Dealer, consumers can log on to www.carfax.com click on "find a dealer" and enter their zip code.

"An airbag unit is there to save lives whenever they are needed," said Gamache. "We want to ensure that drivers are made aware of this potentially fatal scam and hopefully help those who may be affected."