The investigation covers about 990,000 vehicles in the United States that were recalled in 2013 and 2014, the AP said. (http://bit.ly/1FQekjL)

The recall was related to computer software, which may not detect an adult in the passenger seat, resulting in the deactivation of airbags, the AP reported.

The National Highway Traffic Safety Administration said 124 people have complained about the problem happening after repairs were made and said it has opened a "recall query" to assess the effectiveness of the recall fix, which was a software update, the AP said.

In a statement to the AP, Nissan said it believes the update took care of the problem and said the company took additional steps to help dealers address customer concerns not related to the recalls.

Representatives at both Nissan and the NHTSA were not immediately available for comment.

NHTSA said Nissan and Infiniti owners complained that after getting recall repairs, the passenger air bag status light stays on, indicating the air bag is turned off even though an adult is sitting in the seat, the AP said, citing documents posted by the safety regulator on Sunday.

The recall affects the Altima midsize car, Leaf electric car, Pathfinder SUV and Sentra compact models from the 2013 and 2014 model years, NV200 Taxi van and Infiniti JX35 SUV from 2013. Also covered are the Infiniti QX60 and Q50 SUVs from 2014, AP reported.

About a year ago, Nissan recalled 1,053,479 vehicles globally, mostly in the United States, to fix the software.

The company at the time identified two accidents in which the passenger airbag did not deploy, according to the NHTSA documents, but a Nissan spokesman said the company could not draw any conclusions about that being related to the software issue.

(Reporting by Shivam Srivastava and Zara Mascarenhas in Bengaluru; Editing by Leslie Adler)