Jeep claims its plug-in vehicles can drive up to 34 or 40 kilometres in electric mode.
Many owners complain their 4xe model almost constantly runs the gasoline engine in cold weather.
This is due to an engineering decision made by Stellantis.
A Seattle law firm is looking into complaints about the Jeep Wrangler and Grand Cherokee 4xe models from owners who feel they have been misled by Stellantis.
The issue comes from the fact that the company advertises these two plug-in hybrid models as having an all-electric range of up to 21 or 25 miles (34 or 40 kilometres).
Jeep says this should be enough for drivers to complete most of their around-town journeys without burning a drop of fuel.
Many owners have now found that while this claim is true in the summer, it doesn’t apply to the colder months.
Now, everyone who buys an electric or plug-in vehicle should be aware that the electric range will be reduced significantly by cold weather, but this is not exactly the problem here.
Indeed, while Jeep owners do complain that their vehicles almost exclusively run on gasoline power throughout the coldest months of the year, the issue is not due to a lack of range.
In fact, even when drivers charge their vehicle’s battery fully before leaving home, they might not be able to drive on electric power alone over any distance at all.
This is due to a programming decision by Stellantis engineers in response to a problem with the gasoline engine that can be brought on by rapid changes in temperature.
In any gasoline engine, seals and gaskets endure rapid shrinking and expansion cycles when the engine warms up and cools down in the winter. This could cause a small amount of gasoline to make its way into the oil pan, where it evaporates once the engine gets sufficiently warm during the next drive.
If this gasoline doesn’t evaporate, it can start to dilute the oil, which could result in severe damage to the engine due to a lack of lubrication.
Since plug-in hybrid vehicle normally only run their combustion engines for short periods at a time, they are not always able to evaporate the gasoline that gets into the oil, especially when it is cold outside.
This is why Stellantis engineers created a mode called FORM (Fuel and Oil Refresh Mode) in the 4xe powertrain control module that runs the engine up to temperature for a set period of time after each start.
Unlike in most other PHEVs however, this mode leaves the engine running for so long that it is almost impossible for many owners to drive only on electric power during their commute for months at a time.
To add insult to injury, 4xe models are significantly more expensive than their gasoline-only counterparts, with the Grand Cherokee 4xe starting at $77,390 compared to the $53,740 price tag of the regular Grand Cherokee.
If the law firm decides that there are grounds for litigation, Stellantis could be sued for false advertising in the near future.
Source: Keller Rohrback