The investigation covers 320,000 vans from the 2003 and 2004 model years.
The National Highway Traffic Safety Administration says it has received six complaints about the front air bags suddenly inflating while the vans were being driven. Three people said they were hurt.
The agency will determine if the problem is serious enough to cause a recall.
The minivans have air bag control circuits that were linked to recalls last year of more than 1.8 million older-model Chrysler and Toyota vehicles worldwide.