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Recent heat pump failures - software issue?

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I just received a follow-up questionnaire from Transport Canada after making my submission regarding this issue.

Hello,

Thank you for taking the time to report this matter to Transport Canada. We have an active defect investigation for performance issues with the heating and cooling system on Tesla Model 3 and Y vehicles in cold weather conditions. We request that you complete the attached questionnaire, in order to provide additional details which will assist in our investigation.

  1. What were the weather conditions on the day of the incident?
    1. Outside temperature?
    2. Was it snowing?
  2. Was the vehicle on charge prior to the trip?
  3. Had you preconditioned the cabin prior to use?
  4. When you noticed the heat stopped working:
    1. Was the vehicle parked or did it fail while driving? If so, how long had the vehicle been driven prior to failure?
    2. What speed were you travelling at?
    3. What was the state of charge?
    4. What accessories were in use?
    5. What temperature was the heat set to?
    6. Were you using the “auto” temperature function?
    7. What did the interior cabin temperature drop to?
    8. Did the heat ever return? And if so, under what conditions?
    9. How long did you have to drive without heat?
    10. Did the windshield or front windows fog/frost up?
  5. Have you received any warning messages relating to the HVAC system?
  6. Did you have the issue diagnosed?
    1. If so, which components were replaced?
    2. Could you attach a copy of the work order?
  7. Has this happened before?
  8. When charging at a Supercharger, did the vehicle have heat?


Thank you,



Defects and Recalls | Défauts et Rappels

Transport Canada | Transports Canada


Motor Vehicle Safety | Sécurité des véhicules automobiles

80 rue Noël street, Gatineau, Québec, J8Z 0A1

Government of Canada | Gouvernement du Canada
 
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i have a model 3. i saw them move when i turned on my climate while using a heat gun to make sure it wasn't ice that was blocking the louver. i watched it move, but still didn't have heat, so its currently in for service and they found it was the compressor that failed.
Well I got the car back today heat works so far. Saw your car there ( outside ) hopefully they get it fixed for you soon.
 
Well I got the car back today heat works so far. Saw your car there ( outside ) hopefully they get it fixed for you soon.
Thanks. I’ve been checking the app and saw it was parked inside for the weekend, then it went outside and plugged into a block heater or something. Took several hours to increase by 1%. Wasn’t worried though as it was 75% when I dropped it off last week.
 
Thanks. I’ve been checking the app and saw it was parked inside for the weekend, then it went outside and plugged into a block heater or something. Took several hours to increase by 1%. Wasn’t worried though as it was 75% when I dropped it off last week.
Yes they only have level 1 there.
I alsi kept checking app and yesterday was in service mode all day so when you see that things are looking up.
 
I just received a follow-up questionnaire from Transport Canada after making my submission regarding this issue.

Hello,

Thank you for taking the time to report this matter to Transport Canada. We have an active defect investigation for performance issues with the heating and cooling system on Tesla Model 3 and Y vehicles in cold weather conditions. We request that you complete the attached questionnaire, in order to provide additional details which will assist in our investigation.

  1. What were the weather conditions on the day of the incident?
    1. Outside temperature?
    2. Was it snowing?
  2. Was the vehicle on charge prior to the trip?
  3. Had you preconditioned the cabin prior to use?
  4. When you noticed the heat stopped working:
    1. Was the vehicle parked or did it fail while driving? If so, how long had the vehicle been driven prior to failure?
    2. What speed were you travelling at?
    3. What was the state of charge?
    4. What accessories were in use?
    5. What temperature was the heat set to?
    6. Were you using the “auto” temperature function?
    7. What did the interior cabin temperature drop to?
    8. Did the heat ever return? And if so, under what conditions?
    9. How long did you have to drive without heat?
    10. Did the windshield or front windows fog/frost up?
  5. Have you received any warning messages relating to the HVAC system?
  6. Did you have the issue diagnosed?
    1. If so, which components were replaced?
    2. Could you attach a copy of the work order?
  7. Has this happened before?
  8. When charging at a Supercharger, did the vehicle have heat?


Thank you,



Defects and Recalls | Défauts et Rappels

Transport Canada | Transports Canada


Motor Vehicle Safety | Sécurité des véhicules automobiles

80 rue Noël street, Gatineau, Québec, J8Z 0A1

Government of Canada | Gouvernement du Canada
I got the same thing yesterday, filled it out, sent it back, linked my horror story YouTube video with time stamps of key events in the bottom of my reply. It's great that it was fixed, but software causing hardware failure - that's not so good and next to zero transparency around that. I wonder what will happen to people who move up north 4 years later, experience their first winter only to realize their compressor/supermanifold requires replacement - one that should have been covered by the warranty (recall?), but by not experiencing real cold temps you'll never know. On the one hand we have to give credit where it's due - an OTA software update fixing a hardware issue is amazing, but how many compressors out there are already badly worn/degraded due to the time running the "bad" firmware release? Sounds to me like a lot of ticking time bombs...
 
I got the same thing yesterday, filled it out, sent it back, linked my horror story YouTube video with time stamps of key events in the bottom of my reply. It's great that it was fixed, but software causing hardware failure - that's not so good and next to zero transparency around that. I wonder what will happen to people who move up north 4 years later, experience their first winter only to realize their compressor/supermanifold requires replacement - one that should have been covered by the warranty (recall?), but by not experiencing real cold temps you'll never know.
If it's actually a HW issue, there will be a recall and they'll be forced to replace everyone's compressors and supermanifolds, regardless of where the car is being driven.
 
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I got the same thing yesterday, filled it out, sent it back, linked my horror story YouTube video with time stamps of key events in the bottom of my reply. It's great that it was fixed, but software causing hardware failure - that's not so good and next to zero transparency around that. I wonder what will happen to people who move up north 4 years later, experience their first winter only to realize their compressor/supermanifold requires replacement - one that should have been covered by the warranty (recall?), but by not experiencing real cold temps you'll never know. On the one hand we have to give credit where it's due - an OTA software update fixing a hardware issue is amazing, but how many compressors out there are already badly worn/degraded due to the time running the "bad" firmware release? Sounds to me like a lot of ticking time bombs...
Same!

I was actually quite interested in question 5:
5. Have you received any warning messages relating to the HVAC system?

We did of course get the "Cold Weather Driving Tips" pop-up at the start of January (I think it came with the .6 update?) which isn't great for Tesla since they knew about the issue and told no one officially.
 
Same!

I was actually quite interested in question 5:
5. Have you received any warning messages relating to the HVAC system?

We did of course get the "Cold Weather Driving Tips" pop-up at the start of January (I think it came with the .6 update?) which isn't great for Tesla since they knew about the issue and told no one officially.
There was lot of car on November/December in here Finland where was heating issues.
 
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Same!

I was actually quite interested in question 5:
5. Have you received any warning messages relating to the HVAC system?

We did of course get the "Cold Weather Driving Tips" pop-up at the start of January (I think it came with the .6 update?) which isn't great for Tesla since they knew about the issue and told no one officially.
Many of us (including me) received a VCFRONT _a447 error when the heating failed.
 
Last edited:
Here's the Twitter post Munro referenced:

Interesting reply, basically matches my theory about what's going on:

Here's another reply:

So I learned that there is a normally a device called a suction accumulator that comes just before the compressor in the suction line, that is supposed to prevent the compressor from taking in liquid refrigerant.They're apparently used in heat pumps and other situations where liquid flooding back into the compressor is likely (not needed in AC systems which would always have a much higher evaporator temperature). Although I'm not sure how this device is supposed to work properly in a car, given that cars are mobile, and can accelerate, brake, turn, and park on slopes. I would expect the refrigerant to slosh around in there and possibly get drawn into the compressor as a liquid if you for example accelerate, brake, or turn hard when it's extremely cold outside.

I wonder if Tesla is simply being too aggressive with the heat pump and needs to back off a bit in their algorithm. For example, instead of allowing the heat pump to take energy from the atmosphere down to -10°C, maybe they should switch to COP=1 mode at say -6°C. It could be that at -10°C, the heat pump would normally still be able to operate (with some liquid refrigerant in the accumulator) without compressor damage if the vehicle does not move, but extreme moves that cause refrigerant to slosh around still cause minor damage to the compressor as the refrigerant sloshes around, and this damage eventually accumulates to the point where the compressor fails.