2015 Dodge Journery. Picture: 123RF
2015 Dodge Journery. Picture: 123RF

Washington — Fiat Chrysler said on Friday it was recalling 4.8-million US vehicles over a defect that could prevent drivers from deactivating cruise control, and warned owners not to use the function until they got software upgrades.

The Italian-American vehicle maker said no injuries or crashes were related to the large recall campaign but said it had one report of a driver of a 2017 Dodge Journey rental car unable to deactivate the cruise control.

Fiat Chrysler, which in 2015 was hit with penalties from US regulators totalling $175m for safety lapses, did not say how much the recalls would cost.

The recall addresses what Fiat Chrysler called an "extremely rare" series of events that could lead to drivers being unable to cancel cruise control.

The National Highway Traffic Safety Administration (NHTSA) said on Friday it "strongly encourages vehicle owners to follow a warning" to stop using cruise control on the recalled vehicles until repaired.

NHTSA said drivers could overpower the system by forcefully applying the brakes until the vehicle stopped. Fiat Chrysler also said the vehicle could be stopped by shifting into neutral and braking.

Fiat Chrysler shares fell more than 2% in premarket trading in New York on the recall. The company noted that at times cruise control systems automatically initiated acceleration to help vehicles maintain driver-selected speeds, including when going up an incline. If an acceleration occurred simultaneously with a short-circuit in a specific electrical network, a driver could be unable to deactivate the function.

Fiat Chrysler said vehicles may be placed in park once stopped, at which point cruise-control is cancelled.

The recall involves a group of petrol-powered vehicles with automatic transmissions from various model years built from 2014 through to the 2019 model year. Most of the vehicles being recalled cover the 2014-2018 model years.

Fiat Chrysler said it was recalling an unspecified number of additional vehicles in Canada, Mexico and other markets, and recalling some Fiat Fremont vehicles built on the same platform as the Dodge Journey. The company said it was also warning owners in other markets not to use cruise control until recalls were completed.

Fiat Chrysler said it uncovered the issue through tests its engineers had conducted.

"Notwithstanding the extraordinary circumstances that must exist before a customer would experience a problem, we are taking this action because we are fully committed to vehicle safety," Mark Chernoby, Fiat Chrysler’s chief technical compliance officer, said in a statement.

"We have a remedy and a widespread network of engaged dealers who are preparing to deliver service. ... We urge customers to follow the instructions on their recall notices."

Fiat Chrysler said the recall repairs were free of charge and that would will begin alerting affected customers as early as next week.

Fiat Chrysler has vowed to improve safety procedures after the NHTSA in 2015 imposed $175m in civil penalties for safety lapses.

In July 2015, Fiat Chrysler agreed to a $105m settlement for mishandling nearly two dozen recall campaigns covering 11-million vehicles. It agreed to a three-year consent agreement and monitoring by former transportation secretary Rodney Slater. It was separately fined $70m by US regulators in 2015 for failing to report vehicle crash deaths and injuries since 2003.

In 2015, Fiat Chrysler booked a €602m after-tax charge, mainly for estimated future recall costs.