A few Tesla owners in extremely cold climates have been experiencing an issue that has resulted in the complete failure of the heating in their Telsa Model 3 and Tesla Model Y vehicles.
— Tyler Selvig (@TSelvig) December 30, 2021
The issue is reportedly due to the air inlet to the heat pump getting frozen open, resulting in the sensors reporting a malfunction and the whole system shutting down.
2) One of the observed causes of a climate failure that has been diagnosed is the front air intake flap freezing open, and blasting cold air into the system when driving on the highway, which is preventing the heat pump system ability to work correctly.
— TREV PAGE (@Model3Owners) January 12, 2022
In theory, the system should still work when the flap is frozen open, meaning the issue can be ameliorated if the sensors could be ignored.
According to Tesla insiders, the company is working furiously on a fix for the potentially deadly issue, which leaves Tesla owners unable to heat their vehicles when they need it the most.
Now according to the changelog of the Tesla software update 2021.44.30.7 the company has released a workaround for the issue.
According to NotATeslaApp:
This release includes changes to how the climate system works in vehicles with a heat pump. If you have experienced a lack of heat in your vehicle, this update may solve the issue by allowing the heat pump to work at lower temperatures.
Driving long distances in extreme weather always carries some risk. Drive Tesla Canada recommends:
“Current mitigations are to precondition the vehicle 30-60 minutes prior to departure, use recirculating air mode and use auto mode. Symptoms may still occur when driving in climates -15°C and below. If heat does not return please park vehicle in a warmer location and allow vehicle to warm up.”