Has your cabin heat stopped working?
Your heat, and your Tesla has been performing well so far but suddenly you get a warning message on the touchscreen that reads “cabin climate control system requires service” and your car starts blowing cold air instead of heat.
This can be very uncomfortable for you and your passengers especially in the middle of winter when temperatures can drop to very low degrees such as -10 degrees in places like Minnesota and you have a long commute ahead of you.
Here are some basic DIY fixes before calling Tesla
Try soft reset first:
Hold both scroll wheels and the brake down and until the MCU shuts down and reboots.
The soft reset is a temporary solution if the problem is software or mechanical. It will bring back the heat for about 10 minutes before it blows cold air again.
There two types of reboots: two thumb salute for MCU reboot and Power Off in Safety & Security for full reboot
In Model 3 the brake doesn’t do anything during MCU reboot, and you do not need touch the brake on Power Off.
Tap on the climate menu. This should either bring a menu for further instructions or bring up a message that says “climate keeper unavailable due to system fault”.
If that doesn’t work, try deep sleep:
Unplug all accessories (USB and power accessories), turn off Sentry Mode, log out of all apps and disconnect stats web sites and leave the car alone for a few hours.
If you find that you can sort out the cabin heat problem on your own schedule a service appointment.
When you schedule a service appointment, request Tesla to fix it sooner since you lack heating capabilities or try scheduling Mobile Service, as you’ll get a quicker appointment with a shorter wait.
Why has the cabin heat stopped working?
1. Software failure in heat pump valve
From 2020 to 2022 thousands of Tesla owners complained about their vehicles not heating up in extremely freezing weather.
The problem arose from faulty software that caused a valve within a heat pump to stay open.
Tesla issued a recall to address the issue. 26,681 Model S, X, 3, and Y vehicles from the 2021 and 2022 model years were involved in the recall.
The manufacturer began equipping some of its vehicles with a heat pump in late 2020. A heat pump operates like an air inverse conditioner, moving existing heat instead of generating it like a conventional heater in vehicles.
Tesla and other electric vehicles often apply a heat pump to warm the cabin in extremely cold temperatures.
This is because it consumes less energy and therefore doesn’t diminish the vehicle’s range.
A firmware update should fix the heating problem. Owners of affected vehicles were advised to install the latest firmware in their cars using an over-the-air update.
This heating malfunction which left some Model 3, S, X, and Y owners without heat in extremely cold temperatures in the winters of 2020 to 2022 was fixed by newer firmware updates, including version 2021.44. 30.7 and later.
Elon Musk said the firmware fix would recalibrate heat pump expansion valve.
You needed stay connected to Wi-Fi to enable your Tesla can download the latest version as it became available.
You also needed to confirm whether your heating operation was intermittent. Was the heat coming on then going off?
Did your heat afterwards recover and revert to work correctly, usually after parking the electric vehicle in a warmer area?
Another fix was to park in a warm place like a heated garage.
Tesla would have asked you if in affected batch to set your Climate to “auto”.
Auto button was supposed to be blue in full Auto mode and only change the set temperature to your comfort level as this was the most efficient heating/cooling setting.
They did not recommend an in-person service visit for this issue
If you still have cabin heat problems in temperate weather, check your VIN number on the Tesla or NHTSA website to see if your vehicle was part of that recalled batch.
Some Tesla service centers told affected customers that this was a hardware issue coming from the air intake of the heat pump where a “flap,” or maybe a valve, got stuck with an ice buildup.
Tesla had parts of their heat pump system or the whole heat pump system replaced.
1. Heat pump failure
How does the cabin heater work in a Tesla?
The heat pump pulls excess heat from the powertrain to maximize Supercharging speeds and driving range in cold weather.
Tesla vehicles equipped with heat pumps can use heat generated by the battery and drive units to warm the cabin, save energy and improve range on long drives.
Traditionally, EVs used resistive heaters to generate heat when needed. Resistive heaters draw a lot of current, which can take a heavy toll on the battery, especially in very cold climates.
Heat pump harness residual heat to regulate the temperature efficiently. A heat pump is said to reduce energy consumption in winter.
Faulty heat pumps need replacement at Tesla service center.
Schedule service in the app for heat pump problems.
Bring your car in to Tesla service center. They will give you a loaner Model S as they wait to order parts and fix your car.
When you driving and are freezing you can turn up the heated seats.
Also go to an outdoor super charger and the heat will kick in again as the battery preconditions but when you leave the station the heat will turn off.
A compressor sits at the front of the car and draws power from the car’s battery pack or Energy Storage System, which is located at the rear.
The compressor, like in IC engine-powered car, pushes the refrigerant through the chilling unit and cools the air before reaching the AC vent.
A problem with the compressor may lead you needing a compressor replacement.
Tesla engineers reduced the number of parts and the complexity of the heat pump resulting in the invention of the Super Manifold, which is basically a two-layer PCB assembly.
It has all the refrigerant channels in the front and pipelines connecting everything together. A similar approach is at the back with the coolant components, which are all plumbed together.
The Super Manifold eliminates about 20 separate parts. The same approach was made to replace the controlling valves with a single assembly, which they called the “octovalve.”
A Super manifold may cause heating problems and this require replacement at service center.
The high-voltage AC compressor has lines that feed into an aluminum refrigerant manifold which contains an accumulator and condenser hooked to its front.
On the back side of the refrigerant manifold is a coolant manifold, sticking out just behind the strut brace just above the front passenger’s side CV axle.
A problem with the super manifold may lead you needing a manifold replacement.
2. Temperature sensor failure
Have you noticed that your Tesla heating unit is not turning hot? This can be very worrying especially in frosty months of December.
Whenever you try to pre heat the car over the app it says “failed to turn on climate control.”
When you in the electric car, and put on “HI”, it does not warm it up. It’s as if the temperature is always on “LO”.
Tesla advises that if your Tesla fails to turn on climate control, this does indicate an issue.
Try a hard reset (unplugging the 12v) and see if that does anything.
Try powering off the car and letting it sit for a bit to see if that corrects the issue.
Call Tesla support and follow all the troubleshooting steps and try and find a solution.
Call a Tesla service center
This is a common issue and most of the time can be fixed with a software update.
What firmware are you on? The issue with mine was a faulty sensor. Updating to latest firmware actually bypasses these sensors.
A firmware update fixes a faulty sensor and makes the heat is work again.
Service center will order replacement parts for your temperature sensor in the car.
3. PTC heater not working
Pre heat models like those of 2018, use every available current to keep the battery warm.
If your car is just blowing cold air, and the heat isn’t working when you get in or you may have tried to pre heat the car in the morning and it doesn’t work, then your PTC heater has failed.
Check Service mode to see if PTC air heater or coolant heater is working.
If are out of warranty you may not be able to get the replacement and repaired PTC heater for no cost, you may have to pay out of your pocket.
Tesla may give you a loaner while they look at it.
If the heater is good try preheating the car for an hour or before you need to go. Sometimes it takes a little for the heater to get started and it will just blow cold air until the heater gets going
4. Defrost failure
Do you have neither heating nor defrosting capabilities?
Is your heat not working well?
Even if you pre heat the car for 30 minutes like suggested the heat resumes but once you get in the car, it turns cold.
Your car could be lacking defrosting abilities. The defrost button has two modes: cool and heat.
When you press it once, it’s cooling defrost. You need to press it twice in a row to turn on the heat defrost. The icon will turn red.
Try Auto mode, heat in all 3 positions, defrost and heated defrost.
Call roadside service.
No heat in that weather makes the car useless to function and they will support it faster than the app.
5. Outdated software version
Has your heat pump failed in the middle of driving forcing you drive in warm large coat, blankets and even alternating driving hands because they were freezing if you have no heated steering wheel?
If you live near a Service Center Tesla will take your car immediately, no appointment needed as this is considered a safety issue.
When you have defective vehicles that have safety issues you can just bring your Tesla directly to them and get a loaner if they have one and they’ll squeeze you in for service as soon as they can.
Check what software version your car is at.
Update to the latest version overnight and heat will be back to working in the morning.
Maybe due to the contents of specific update or a system reboot caused by an update or due to passage of time the cabin heat will return.
6. Short preconditioning
In winter always have high heat while going in to the drive. If you don’t precondition for thirty minutes, an hour or more, you cabin heat will be chilly.
Depending on the year Tesla uses the heat from the battery pack to heat the cabin. If you don’t precondition long enough, the battery pack will cool down while driving.
A combination of setting a scheduled departure and manually selecting precondition in the app prior to leaving by turning on climate to full high manually preconditions.
If the pack is cooling off too quickly, punch a supercharger into your nav and see if that fixes your issue.
If not then you need a new heater core.
Have a set pre-conditioning schedule in place preferably in a warm garage leave home and when you leave set climate to a good temperature level that can defrost the windshield and take away humidity.