Tesla is recalling nearly 27,000 vehicles due to an energy-efficient design that hinders the machines’ ability to defrost.
As temperatures plunge through the winter seasons, some Tesla owners have been experiencing difficulty with their heating systems. A technical issue with how the heat pump operates is unintentionally causing many of the vehicles to lose heat.
When Tesla introduced the pump in 2020, CEO Elon Musk said it was “some of the best engineering I’ve seen in a while.”
The energy efficient pump is designed to trap and recirculate heat generated by other parts of the car. However, the software issue in question is reportedly causing the pump to open unintentionally, which traps refrigerant inside the evaporator. This then causes the compressor to fail which can reduce temperature inside the cabin. This in and of itself isn’t necessarily a safety issue. However, the issue lies in that this fault reduces the vehicles’ defrosting capabilities.
Some Tesla Models Defrosting Capabilities Not Up to Code
For Tesla owners in colder climates, on-par defrosting is absolutely necessary to drive safely in winter weather conditions. Tesla is currently working on a software patch to fix the issue. In the meantime, the National Highway Traffic Safety Administration (NHTSA) has issued a recall for the affected vehicles.
“Windshield defrost performance that does not fully comply with FMVSS 103 may cause reduced windshield visibility in certain conditions, which may increase the risk of a collision. Tesla is not aware of any crashes, injuries or fatalities related to this condition,” NHTSA said in a statement.
The recall is being issued because the issue may prevent Tesla owners from seeing clearly out of their windshields.
“Decreased defrosting performance may reduce the driver’s visibility, increasing the risk of a crash,” the organization said. They offered an in-depth explanation of the issue in the recall notice. Additionally, they gave an explanation of a potential solution for the problem.
Software Malfunction Causing Winter Driving Safety Issues
“In vehicles built with heat pump, the Electronic Expansion Valve (EXV) may experience controller communication interruptions, after which the EXV driver may attempt to realign the EXV rotor by rotating it in a small increment toward the open direction. When heat pump vehicles delivered with firmware release 2021.44 through 2021.44.30.6 experience such interruptions, the vehicle software does not close the valve, and the accumulation of interruptions and subsequent realignments over extended periods where the vehicle is awake may result in an unintended valve opening event. This, in turn, may trap refrigerant inside the evaporator and may deplete the refrigerant from the active components in the system. The depletion may result in fail-safe compressor stoppage, and cause loss of cabin heating, particularly in temperatures –10 C or colder. While the windshield defrost system continues to operate with the condition present, defrost performance may not fully comply with FMVSS 103.”
Affected Tesla vehicles include “certain 2021-2022 Model 3, Model S, Model X, and 2020-2022 Model Y vehicles.”
An upcoming over-the-air software update is expected to fix the issue. The update will re-introduce a command that should solve the issue. The command will prompt the heat pump to close properly and prevent refrigerant from entering the evaporator.