Tesla owners in Western Canada and Alaska have been dealing with a lack of cabin heat in Model 3 and Model Y vehicles when temperatures plunge below freezing. Tesla says the lack of heat stems from a recent firmware update affecting the heat pump. In response, the all-electric automaker has attempted to fix the problem with a second Over-The-Air update.
Some owners have been dealing with this issue since last winter, but now the situation has become so dire both the National Highway Traffic Safety Administration and Transport Canada have opened investigations into the problem. Transport Canada said it has concerns that a malfunctioning HVAC system “may affect windshield defogging/defrosting and therefore driver visibility.” Over the weekend, Tweets authored by Tesla CEO Eon Musk indicated a firmware path was being rolled out to recalibrate the heat pump expansion valve.
There are reports that several owners have had parts of the heat pump replaced, or in some cases had the heating system replaced entirely. Unfortunately for owners, it seems the issue is deeper rooted than a simple firmware fix leaving some deeply dissatisfied with their ‘luxury’ vehicles.
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The heat pump system is expected to work even in temps colder than -22F. It uses a pair of loops that compress and expand refrigerant from liquid to gas and back to liquid in order to generate heat which is then pumped into the cabin through the HVAC system. Tesla Model Ys and updated Model 3s equipped with Tesla’s new heat pump system have a set of grille louvers designed to open and close based on certain conditions. They’re expected to close during normal operation to improve vehicle aerodynamics, but default to open when the vehicles are at rest, plugged into Superchargers, or home chargers. The issue apparently doesn’t affect older Model 3 electric vehicles.
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Well, in the frigid north, these louvers are seeing a build-up of snow and ice which is keeping them from closing. This continual flow of cold air at speed is causing the vehicle to think there’s a fault in the heating system which in turn causes the heat pump to shut down. The firmware patch seems to address the issue by simply tricking the vehicle into ignoring the cold air input from the temp sensor in order to keep the heat pump running.
Of course, that’s not a permanent solution as the freezing cold air is actively chilling the heated fluid and forcing the heat pump to work overtime, this can and will likely cause premature failure of the heat pump. It’s unclear if the company will work to change the default setting of the louvers to close at rest in order to keep the flaps from freezing in the open position or if a recall will be required to replace the hardware.
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