A safety issue with front-seat air bag sensors in about 990,000 Nissan and Infiniti vehicles that led to a recall last year may still be a big problem. Government investigators are looking into whether the repairs made during the recall actually took care of the issue.

The recalls in 2013 and 2014 were conducted because the "Occupant Classification System" might not recognize when someone is sitting in the front passenger seat. The computer might show the seat as being empty, which would mean that if there's a car accident, the air bags would not deploy.

The current National Highway Traffic Safety Administration (NHTSA) investigation was prompted by complaints from 124 people indicating the air bag problems persisted, according to the Associated Press.

Related: More Recalls and Product Alerts in SafeBee.com’s Recall Center

Vehicles recalled include the 2013 and 2014 Nissan Altima, Leaf, Pathfinder and Sentra, along with the 2013 Infiniti JX35 and 2014 Infiniti QX60 and Q50. The recall is unrelated to the larger Takata air bag recall that affects numerous makes and models from multiple manufacturers.

According to the Associated Press, one Nissan Pathfinder owner reported to NHTSA the SUV was taken to the dealer four times for two recalls, but the air bag indicator light still shows no one is sitting in the seat even when someone is.

A Nissan Leaf owner told NHTSA: "While driving, the right front air bag light activated, indicating that the air bag was off. This occurred and continues to occur regardless of the passenger's weight or the absence of a passenger. Nissan serviced the vehicle once before with a 'software update' that did nothing to correct this very serious defect."

NHTSA's investigation is looking at whether the software update Nissan came up with was the proper solution.

"Since the recall was launched, Office of Defects Investigation (ODI) has received 124 complaints alleging problems with the OCS (Occupant Classification System) after the recall repairs and/or other OCS related repairs were made by Nissan/Infiniti dealers," according to the investigation announcement posted on the NHTSA website. "The majority of the complaints allege the passenger air bag status light stays on (i.e., indicating passenger air bag is turned off) for adult front passengers. Some of the complaints state the dealers have made multiple repairs but the problem still persists."

Nissan maintains the problem was properly handled.

“Nissan Group believes the recall remedy was effective and appropriately addressed the safety defect,” Nissan North America Inc. spokesman Steve Yaeger said in a statement. “Nissan and Infiniti also took additional steps to help dealers address residual customer concerns unrelated to the recall and to maintain high level of customer satisfaction.”

Related: Auto Industry Issues Record Number of Recalls in 2014

Consumers, though, are left in an uncomfortable situation of being told that a safety problem with their vehicles that was supposed to be fixed might not be. The automotive website Edmunds.com recommends that owners of the affected Nissan and Infiniti vehicles stay in touch with the service departments of their dealerships for next steps.

And if you have the recalled vehicles, be aware when the light comes on indicating no one is sitting in the passenger seat when someone is, the air bag will not deploy if there's a collision.

“The current Nissan and Infiniti air bag recall investigation is a very good example of why it is so important for vehicle owners to be aware of any recalls or Technical Service Bulletins (TSB) they have on their cars, and have regular communication with their dealership,” said Keith Andreasen, master automobile technician and consultant to CarMD.com. “In this case, any owner of an affected Nissan or Infiniti vehicle should continue outreaching to their local dealer to demand results.”

He explained that it's still best to stick with the dealer in cases like this.

“In the case of a recall or TSB, it is usually in the vehicle owner’s best interest to work directly within their dealer network rather going outside the network to get help," Andreasen said. "As a manufacturer that often scores high reliability marks, Nissan is very capable of solving these issues. The vehicle owner needs to remain proactive by staying on top of the situation until it is resolved to their satisfaction.”

For more information, vehicle owners can call Nissan at 1-800-647-7261, NHTSA's Vehicle Safety Hotline at 1-888-327-4236 or visit the agency's website at www.safercar.gov.

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Mitch Lipka is a consumer columnist and product safety expert. He was the 2011 recipient of the "Kids Best Friend Award" from Kids In Danger for his commitment to reporting on children’s product safety.