(Adds Honda comment in paragraph 7)
DETROIT Aug 4 (Reuters) - U.S. safety regulators have upgraded an investigation of an estimated 335,195 Honda Accord sedans a step closer to a recall after receiving almost 300 complaints that air bags can deploy when the car door is shut with too much force.
The U.S. National Highway Traffic Safety Administration (NHTSA) said in documents filed online on Friday the investigation was upgraded to an "engineering analysis" from a "preliminary evaluation" of the 2008 four-door models made by Honda Motor Co .
An engineering analysis is a step that can lead to a recall if regulators determine the manufacturer needs to address a safety problem.
The NHTSA said it had identified 293 incidents of alleged inadvertent deployment of driver or passenger side air bags. Fourteen people were injured because of the problem, according to agency documents.
In some cases, the side seat-mounted torso air bag can deploy as well, the NHTSA said.
The agency said it was investigating the risk of air bag deployment injuries to occupants in vulnerable positions. Regulators opened the initial preliminary evaluation in late January.
Honda, the No. 2 Japanese automaker by U.S. sales, said it was aware of the upgraded investigation "based on a small number of complaints," adding that "Honda will continue to cooperate with the NHTSA through the investigation process, and we will continue our own internal review of the available information."
In June 2008, near the end of model 2008 Accord production, Honda changed the crash parameter for door-closing force in the electronic control unit's software code to reduce the incidents of inadvertent side air bag deployments, the NHTSA said. Regulators found the number of inadvertent air bag deployments had fallen significantly after that.
Honda said the two-door Accord used a different software crash parameter than the four-door model, according to the NHTSA.
In one incident last fall, an owner said he had stopped at a gas station so his fiancée could purchase a drink. When she closed the door, the passenger-side curtain air bag deployed, striking their 9-year-old son, according to a complaint filed with the NHTSA.