The carmaker will also offer to buy back nearly half-a-million of the vehicles it has recalled.

Fiat Chrysler has also agreed to being monitored for the next three years, which includes hiring an independent monitor approved by NHTSA to assess, track and report the company’s recall performance.

The enforcement action comes after a 2 July public hearing at which NHTSA officials outlined problems with Fiat Chrysler’s execution of 23 vehicle safety recalls covering more than 11 million defective vehicles. Fiat Chrysler has since admitted to violating the Safety Act in three areas: effective and timely recall remedies, notification to vehicle owners and dealers and notifications to NHTSA.

The NHTSA’s Secretary Foxx said the action “holds Fiat Chrysler accountable for its past failures, pushes them to get unsafe vehicles repaired or off the roads and takes concrete steps to keep Americans safer going forward. This civil penalty puts manufacturers on notice that the Department will act when they do not take their obligations to repair safety defects seriously.”

The penalties came just days after the carmaker issued a safety recall covering 1.4m vehicles in the US, after security researchers demonstrated that one of its cars could be hacked and taken control of.

Chris Valasek and Charlie Miller recently remotely hacked into a 2014 Jeep Cherokee, proving that they could disable the SUV’s engine functions and take control of features such as air conditioning, locks and the radio remotely.

The flaw was exposed in an article published by Wired magazine.

Fiat Chrysler said exploiting the flaw "required unique and extensive technical knowledge, prolonged physical access to a subject vehicle and extended periods of time to write code" and also said that manipulating its software "constitutes criminal action".

The recall applies to certain vehicles equipped with 8.4-inch touchscreens among the following models:

• 2013-2015 MY Dodge Viper specialty vehicles
• 2013-2015 Ram 1500, 2500 and 3500 pickups
• 2013-2015 Ram 3500, 4500, 5500 Chassis Cabs
• 2014-2015 Jeep Grand Cherokee and Cherokee SUVs
• 2014-2015 Dodge Durango SUVs
• 2015 MY Chrysler 200, Chrysler 300 and Dodge Charger sedans
• 2015 Dodge Challenger sports coupes

Customers affected by the recall will receive a USB device that they may use to upgrade vehicle software, which provides additional security features independent of the network-level measures. Alternately, customers may visit http://www.driveuconnect.com/software-update/ to input their Vehicle Identification Numbers (VINs) and determine if their vehicles are included in the recall.