It says drivers can potentially get around the problem by using the breaks constantly, to the point where the vehicle is able to stop, which would allow cars to be placed in park and cruise control to be disabled.
It warned owners, including those outside the United States, not to use the function until they get software upgrades.
While the flaw would require an unlikely series of events to happen simultaneously for an incident to occur, the company said it was committed to the safety of consumers driving any of the nine affected models of cars, vans, trucks and SUVs from model years 2014 to 2018 and in one case the 2019 model year. The company said it was also warning owners in other markets not to use cruise control until recalls are completed. 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".
The recall includes 15 Jeep, Dodge, Chrysler and Ram models from six model years. Shifting into park would cancel the cruise.
Fiat Chrysler said drivers could still stop their auto by continuously putting on the brakes or by shifting into neutral gear and braking. Included are 4.8 million vehicles in the USA, another 490,000 in Canada and an undetermined number in Mexico and other countries. That being said, the company is unaware of any injuries or accidents related to recall even though affected models have clocked over 200 billion miles (321 billion km).
The issue, the automaker insists, depends on "extraordinary circumstances" taking place, according to Mark Chernoby, Fiat Chrysler's chief technical compliance officer.
Fiat says a "widespread network" of dealers are prepared to help.
Fiat Chrysler will begin notifying customers as early as next week.
The U.S. National Highway Traffic Safety Administration, the government's road safety agency, on Friday urged drivers not to use the cruise control until repairs are made.
In July 2015, Fiat Chrysler agreed to a $105 million settlement for mishandling almost two dozen recall campaigns covering 11 million vehicles.