The company did not indicate whether the defect was involved in any reported accidents, in the letter it sent to the National Highway Traffic Safety Administration.
In the affected vehicles, the software that activates the airbags may misclassify "an occupied front passenger seat as empty," Nissan said.
In those cases, "there may be no warning that the air bag may not deploy in a crash where it is designed to deploy, potentially increasing the risk of injury to the front passenger seat occupant," it warned.
The massive recall comes as US auto giant GM finds itself in the crosshairs of a growing scandal over its failure to react to an ignition switch defect linked to 12 deaths.
GM is now facing multiple investigations by US authorities over the issue, which was detected at the pre-production stage as early as 2001. GM waited until last month to recall 1.6 million vehicles in North America.