Jeep has two plug-in hybrid vehicles in the wild and likely more coming, but the automaker’s parent company, Stellantis, is looking at a potential class action for how it describes the 4xe PHEV system’s functionality. The vehicles feature a unique engine management system that can make it impossible to use electric propulsion when temperatures drop. Law firm Keller Rohrback (KR) is placing ads on social media to find owners whose experience driving the Wrangler 4xe and Grand Cherokee 4xe in cold weather.

KR says it is investigating claims that Jeeps falsely advertised the capabilities of its novel plug-in hybrid SUVs. The firm’s landing page for the issue alleges that people cannot use the available electric-only drive modes “for months at a time during cold weather.” Jeep states a 25-mile electric range for the Grand Cherokee 4xe and 21 miles for the Wrangler 4xe.

 It’s important to note that the law firm is not claiming that people are upset over the cold weather range, which can be drastically lower than the range in warmer temps. The firm is investigating issues that arise from the expansion and contraction of gaskets and seals in the oil system. As the seals change shape, they allow small amounts of gas to get into the oil, which the engine’s heat would generally burn off. 

In hybrid vehicles, the internal combustion engine doesn’t run as often and can fail to evaporate the gas. Jeep’s workaround is a Fuel and Oil Refresh Mode, or FORM, which activates the engine to evaporate gas from the oil. KR alleges that in some vehicles, FORM remains active for extended periods, making it impossible to use the electric-only range.

We don’t know how many claims KR has gathered on the issue, but it’s not the only firm chasing Jeep. Another, possibly related suit is in the works from another group of law firms, and some owners have pursued a class action against Jeep over claims the vehicles shut down at speed and display warning lights.