The issue can be triggered when the vehicle accelerates while operating under cruise control, which it might do in order to maintain its speed while climbing a hill, the company said.
The likelihood of this happening is clearly minimal, but all of those involved in examining the issue, including the National Highway Traffic Safety Administration (NHTSA), are recommending that owners of affected vehicles not use the cruise control function until the software can be updated.
The recall covers more than 4.8 million vehicles in the United States and 490,000 in Canada, regulators said.
FCA US LLC claims that cruise-control acceleration can be overpowered by the vehicle's brakes. The agency said that to stop the vehicles, drivers should shift into neutral, forcefully apply the brake and put the vehicle in park once it's stopped.More news: North Korea summit could still happen on 12 June
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The system would then need to increase the speed of the vehicle at the same time there's a short-circuit in a "specific electrical network". That will cancel cruise control. The recalled cars will include several versions of the Chrysler Sedan, some Dodge SUV's, and some Ram pickup trucks.
The safety campaign involves Ram pickups, Jeep Wrangler, Cherokee and Grand Cherokee sport utility vehicles and several Chrysler and Dodge brand models, according to a company statement. Some markets outside the USA, including Canada and Mexico, are also affected, but the total number of vehicles involved globally is not known. Thus stepping on the brake does not disengage the cruise control. Regardless of which option is used, cruise control will be cancelled once the auto is put in park. The only way to stop at that point would be to brake to a full stop. "It was still running at an engine speed to support 70 miles per hour and fighting the brakes".
The issue, the automaker insists, depends on "extraordinary circumstances" taking place, according to Mark Chernoby, Fiat Chrysler's chief technical compliance officer.
The flaw was initially discovered after Fiat Chrysler, which is also known as FCA, tested the vehicles' computer network.