— A Tesla heat pump recall includes more than 26,600 model year 2021-2022 Tesla Model 3, Model S, Model X and 2020-2022 Model Y vehicles to prevent problems with the windshield defrosters.
Tesla believes the problem affects only 1% of the recalled vehicles, but the recall is necessary because software errors may cause valves in the heat pumps to open unintentionally and trap the refrigerant inside the evaporators. This can cause the defrosters to suffer from reduced performance.
According to Tesla, federal regulations require "80% minimum defrost of critical area C at 20 minutes," but a software command found in firmware release 2021.44 through 2021.44.30.6 may prevent the vehicles from meeting federal standards.
A faulty defroster can cause serious problems, but Tesla is not aware of any crashes, injuries or fatalities related to the problem.
The electronic expansion valve (EXV) may experience interruptions of the controller communications which cause the EXV driver to realign the EXV rotor by rotating it in a small increment toward the open setting.
This can eventually cause an unintended open valve which traps refrigerant inside the evaporator and may deplete the refrigerant from the system.
A loss of refrigerant can cause the compressor to enter a fail-safe mode to stop the compressor, preventing the cabin from receiving any heat.
According to Tesla, firmware release 2021.44.30.7 and later releases fix the problem by reintroducing a software command to close the EXV which prevents refrigerant from entering the evaporator. Tesla says no further action is necessary for vehicles equipped with firmware release 2021.44.30.7 or a later release.
A driver will receive an alert and the blower motor in the heating and cooling system remains operational which may at least buy a driver some time before the windshield is covered by frost.
The recall will see Tesla perform over-the-air software updates to keep the defrosters working.
Tesla recall notification letters are expected to be mailed April 1, 2022.
Tesla owners with questions should contact Tesla customer service at 877-798-3752 and use recall number SB-22-18-002.
