HVAC Cooling Performance Degraded

[nayr14]

With spring arriving in the Midwest and the warmer temperatures, I've noticed that my 2018 Model 3 is experiencing issues keeping the cabin cool over a few drives in the last 3 weeks. During the past two summers I've kept the AC around 70-72F in the summer with no issues. This year I'm having to turn it down to 66F when it's 75F and partly cloudy outside. I don't think I've changed

I run ScanMyTesla so I checked the HVAC data (see attachments). Even with the above conditions (75F exterior, 66F HVAC setting) I still see there is power to the PTC heater. The air is somewhat cool but not super cold. The fan speed is also low and the AC compressors duty cycle is very low (10%) with no AC fan running. When I turn the HVAC to 'LO' it blows fast and very cold air.

I haven't gone to a shop to have the AC pressures checked, but based on the above observations I'm thinking there is a sensor issue or a SW update has broke HVAC. Has anyone experienced this behavior before? I'd open a service inquiry with Tesla but I'm out of warranty.

 

[Kimmi]

I was having the same problem starting a couple months ago. I tried to schedule a ranger to come out and do a tire rotation and change the cabin filters but the service center told me I had to bring the car in because there was a recall. After getting the car back they replaced one low pressure sensor and two high pressure sensors and everything is back to normal now. 2001 Long Range delivered December 2020. YMMV.

 

[nayr14]

Does yours have a heat pump? Mine is resistive PTC heat and standard AC.

 

[Kimmi]

Heat pump.

 

[Sziehr]

This is something I just noticed as well. So the whole check pressures is pointless if you max cold max blow it works. This says refrigeration is working. The issue is a sensor not reporting right or a software screw up. I plan to file yet another fun ticket with tesla on this soon. So much fun tesla is. It lives in the shop it seems

 

[RickyFish89]

I've noticed something similar this year. This is only my second summer with the car, got the '21 3 last february, but I must have a bad sensor or software updates have borked it. I keep it on auto and have to drop it Way down before it seems to try to cool with any gusto. What's worse for me is that preconditioning is now almost useless. Like I'll open the app about 5-10 minutes before we leave the playground with my son and it says it's 100F in my car, so I start preconditioning, having it set somewhere between 68-70F. Within 1-2 minutes I get a notification saying it's reached temp which already throws a red flag to me since it probably didn't drop 30 degrees in 2 minutes.. then when we get in the car a few minutes later it is definitely nowhere near 68F and the climate is on, but not acting with much force at all. I'll give it one more firmware update before I try to schedule a service appt. Not sure if the car has a bad sensor that makes it think it's much cooler than it actually is or if a firmware update has purposefully made large changes to AC in an attempt to keep things quieter, more gradual change, or "more comfortable" in ways that I disagree with.

 

[Markpn]

I've noticed something similar this year. This is only my second summer with the car, got the '21 3 last february, but I must have a bad sensor or software updates have borked it. I keep it on auto and have to drop it Way down before it seems to try to cool with any gusto. What's worse for me is that preconditioning is now almost useless. Like I'll open the app about 5-10 minutes before we leave the playground with my son and it says it's 100F in my car, so I start preconditioning, having it set somewhere between 68-70F. Within 1-2 minutes I get a notification saying it's reached temp which already throws a red flag to me since it probably didn't drop 30 degrees in 2 minutes.. then when we get in the car a few minutes later it is definitely nowhere near 68F and the climate is on, but not acting with much force at all. I'll give it one more firmware update before I try to schedule a service appt. Not sure if the car has a bad sensor that makes it think it's much cooler than it actually is or if a firmware update has purposefully made large changes to AC in an attempt to keep things quieter, more gradual change, or "more comfortable" in ways that I disagree with.

Agreed- this problem has really manifested itself when I downloaded 2022.12.3.2. Very frustrating - the outside temp is "never" the same as inside the car (and where i live inside the car is always warmer - Long Beach CA). It was 21C/70F outside yesterday; the inside of the car was hot as heck, and the A/C wouldn't blow cold when set at a comfy 22C/72F (and it was very warm inside the car). When I turned it to LO, the fan and a/c kicked on and the car cooled down. Yay. So, while I expect it to be fixed in a future software update, my question is this- why, if something is working, does a new software update BREAK it? It seems the software is now looking at the outside temp sensor to determine when/if the hvac system will work instead of the inside temp sensor. It's not the first software gremlin we've seen (re: PB thread a good one) - but where is the QC?

Who is testing these updates before they're pushed out? And who is messing with code that is working?? Elon- come on, man. You're a genius, and I love my 2018 Model 3 LR. But these are the sort of little gremlins that will turn your users against you if this can't be done up right. Once something is working - don't touch the code. In the meantime - can I get my hvac system back, please?

 

[nayr14]

It warmed up this weekend and the temperature the auto climate seemed to work well. I've had multiple instances of this issue when the exterior temp is close the HVAC set temp this year.

 

[ATPMSD]

If you are having flow problems you might want to check the cabin air filter, especially after pollen season.

 

[Ken43]

Having some similar issues with my 2018 model 3 RWD LR. When a/c on auto , set on 70F, outside 80F, after 20 or 30 minutes the airflow decreases and interior gets warm. However air feels cool coming out of vent, just reduced flow. Can turn a/c to manual and turn fan to 10 but air flow still reduced.

Then I can turn off a/c and then 30 seconds later airflow returns to normal and is initially cold.

Vehicle is in Tesla shop now and they think the problem is bad actuator vanes and the low voltage controller that supplies them...

(By the way , cabin air filters are new)

 

[Sziehr]

Having some similar issues with my 2018 model 3 RWD LR. When a/c on auto , set on 70F, outside 80F, after 20 or 30 minutes the airflow decreases and interior gets warm. However air feels cool coming out of vent, just reduced flow. Can turn a/c to manual and turn fan to 10 but air flow still reduced.

Then I can turn off a/c and then 30 seconds later airflow returns to normal and is initially cold.

Vehicle is in Tesla shop now and they think the problem is bad actuator vanes and the low voltage controller that supplies them...

(By the way , cabin air filters are new)

Yeah I want to know the result of this. I am in the same spot. I have a bit left on warranty.

 

[Ken43]

Yeah I want to know the result of this. I am in the same spot. I have a bit left on warranty.

Part comes in 6JUN2022 and due to pickup vehicle 7JUN2022. Will report back after a few days later r to make sure fixed problem.

 

[jkeyser14]

My AC in my Model 3 died a couple months ago. Tesla claims it is a bad sensor causing the evaporator to always report -3 degrees. I've been waiting on a replacement part to arrive, but in the meantime 80-90 degree days + solar loads have been rough.

 

[Sziehr]

Oh I know this pain. I went no blower motor 2 years ago due to a shorter motor for 3 weeks in summer. Not even a blower

 

[tone228]

With spring arriving in the Midwest and the warmer temperatures, I've noticed that my 2018 Model 3 is experiencing issues keeping the cabin cool over a few drives in the last 3 weeks. During the past two summers I've kept the AC around 70-72F in the summer with no issues. This year I'm having to turn it down to 66F when it's 75F and partly cloudy outside. I don't think I've changed

I run ScanMyTesla so I checked the HVAC data (see attachments). Even with the above conditions (75F exterior, 66F HVAC setting) I still see there is power to the PTC heater. The air is somewhat cool but not super cold. The fan speed is also low and the AC compressors duty cycle is very low (10%) with no AC fan running. When I turn the HVAC to 'LO' it blows fast and very cold air.

I haven't gone to a shop to have the AC pressures checked, but based on the above observations I'm thinking there is a sensor issue or a SW update has broke HVAC. Has anyone experienced this behavior before? I'd open a service inquiry with Tesla but I'm out of warranty.

I’ve been having this same exact issue but it is intermittent. First time it happened and went away on its own after letting the car sit overnight. 2nd time I rebooted the system and it fixed itself. Now it’s happening again as of the other day. I scheduled a service appointment after the first time it happened but the next available on a day and time that fit my schedule was almost a month out. Luckily I didn’t cancel after it started working again but my concern is the service center won’t be able to replicate the problem. Was hoping someone in here had this fixed by the SC

 

[Ken43]

Update: my actuator vanes and the low voltage controller that supplies them were replaced by Tesla. Unfortunately low air flow / hot interior came back 30 minutes after I picked up vehicle. Took my Tesla back in on for service. Tech did experience the intermittent problem himself today after my u-turn so he knows , the problem is "real". I expect it will be a week before they figure it out and are able to fix it.

 

[ochompsky]

also experiencing the same problems in my 2020P. had the filters replaced recently so that's not the problem. looks like it's time to schedule an appointment.

 

[Fierily]

Same issues with my 2020. It was 90F outside and I set the temp to 68F auto. It set the fan speed to 3. If I manually set the fan speed, it felt cool but not as cold as some days. I looked at my efficiency and it was at 370 Wh/mi which only ever happens when I need defog, so I think the car believes it's colder than it actually is. It's strange because on some days where it's 70-80F, the AC can uncomfortably cold with it set to 68F auto.

 

[CKwik240]

Mine constantly felt like it was warmer than it should be. Is adjust the dropping down and it would cool again for a bit and then feel warm again. Just changed the cabin filters and now it works great. Bought my M3P with some 35k miles and it seems the previous owner didn't bother changing them.

On a side note, who the hell designed the replacement mechanism? I've never run into a more difficult system.

 

[Sziehr]

Update: my actuator vanes and the low voltage controller that supplies them were replaced by Tesla. Unfortunately low air flow / hot interior came back 30 minutes after I picked up vehicle. Took my Tesla back in on for service. Tech did experience the intermittent problem himself today after my u-turn so he knows , the problem is "real". I expect it will be a week before they figure it out and are able to fix it.

So I gotta think it’s part software as it all the sudden hit so many. Like my self. The vanes stopped doing the seek on drive, I no longer hear the faint clicking of the vanes to move into position till I monkey with the up down of them, then suddenly the stepper motor goes to seek mode and finds the positions, then clunk clunk clunk as it steps big time into the proper location and boom sweet sweet air in the right spot, so it is not the blower not blowing and for me it has stopped being the not cold cold air, but it remains the lack of position memory as it was before and it just ends up flipping the vanes into an up park position from the app, I think the APP to cool the car down moves the vanes into a wider distribution and goes hard to get max wide cooling. Then when you get in the easy entry should pull the vanes down to easy entry, then the vanes should move once more per the profile of the user, then boom sweet sweet cold air right where you remember it. This is some sort of screw up with the vanes getting the command to seek and go to position X. Why who the hell knows it is Tesla it is a black box, I am sure if I could tail the logs I would see the missing command or the malformed command coming from the MCU to the body left controller to seek and find vane position X. So till then I have a detailed write up of the steps I have found to get it to fail and to get it back to working but not to keep memory.

Steps to replicate

1. set flow direction to desired orientation.
2. Drive car.
3. Exit allow to go through the easy entry profile.
4. Sleep car.
5. Return to car new session.
6. Enter car in easy entry position.
7. Begin session of define under defined profile.
8. Notice air flow is not as before.
9. Open ac flow controls.
10. Nudge flow up down barely.
11. Listen to car ac control vanes re seek position.
12. Once the clicking of the vanes as completed flow is resorted to desired location.

Change in behavior is the ac control vanes do not reorient on each profile change as should. Screen does not reflect correct placement of controls slats. Moving the direction on screen triggers a re searching of current flap positions and land back on the proper flow.

New issues per 2022.12.x.x

Let me know if this seems similar to your experiences