Ford is recalling up to 850,000 new vehicles, including two of its bestselling cars, over concerns that a software glitch can cause a short circuit that prevents air bags and other safety features from properly deploying in the event of an accident.

The recall affects Ford's Escape compact crossovers, Fusion midsize cars, C-MAX compact MPVs and Lincoln MKZ luxury cars with model years 2013 and 2014. About 746,000 of the affected vehicles are sold in the United States, while some 82,000 are found in Canada. The remaining vehicles are located in Mexico.

Ford says the recall is due to a problem with the cars' restraints control module, which controls many of the safety features, such as the front air bags, side air bags, stability control and seatbelt pretensioners. The defective software could potentially cause a short circuit that would prevent the air bags from being deployed properly in case a crash happens. Additionally, the short circuit could turn on the warning lights for other safety systems and potentially prevent them from working as intended.

Ford says it is unaware of incidents stemming from the problem and will replace the restraints control module on all affected cars for free.

This is the twelfth time Ford had to issue a recall for the Escape crossover, which is the company's third biggest-selling vehicle next to the Fusion and the F-series pickup trucks. Ford has sold more than 208,000 new Escapes this year alone, but has recalled more than that due to a variety of issues, including a fire hazard coolant system caused by leaks that could lead to overheating and carpet padding that could depress the accelerator pads.

"Vehicle launches are complex and each one has its own issues," says a Ford spokesperson. "We work through them and while we know this is an inconvenience for our customers, we are trying to insure their safety."

However, car safety experts believe Ford should create a dedicated team to thoroughly investigate the crossover.

"Our threshold is that when you have more than three recalls, you are in deep water," Clarence Ditlow, executive director of the Center for Automotive Safety, told the Wall Street Journal. "When you have over 10, then you are in trouble."

On Thursday, just a day before Ford announced its recall, Fiat Chrysler Automotives made its own air bag-related recall of around 350,000 vehicles around the world after discovering a defect with the ignition switch that sometimes cut off the power source to the air bags, steering and engine.