Slow heat

Humm, so you are saying it worked before but now it doesn't? With my experience on the previous two PP models, 2017 and 2020, the heat pump was never efficient to heat the cabin in "cold temperature". Here when I say "cold" it is usually below 32°F (0°C). I don't use heat unless the ambient temp gets to the low 30s (single-digit °C) or lower. As you probably know already, at below 14F (-10°C) the heat pump does not work at all. I have tried using preheating several times with my 2017 PP, but it never worked to my satisfaction. The cabin was never warm to the AC set temp and it used the traction battery charge reducing the EV range. So, I stopped using the function altogether. Instead, during winter, I just started a car in HV mode as soon as I get in the car in the morning and used the heat from the engine. I didn't drive the 2020 PP for commuting, so I never needed to do that, but for my 2021 PP, if I do regular morning commuting this winter, I will do the same or maybe use CHG mode on my morning commuting if the price of gas comes down.

 

The coolant replacement is scheduled to be at 100K miles (~160K meters) in the US. It is hard to believe it needs to be replaced so early. As I said, I don't use preconditioning, so I don't know what is the normal change in the performance over a year or two. I also don't use HVAC much 9 months out of a year, except when my wife is riding the car with me, so I don't know how that performance changes over time either. At least for my 2017 PP which is the longest owned PP, I did not feel any degradation in HVAC capability over the 2.5 years I have owned.

 

That's a common issue for me "losing the magic". It seems that way for most anything acquired new these days, again for me anyways. phones, TV's, computers, batteries, etc... If I'm excited about a new model, I find the "magic" usually dies a slow death within a few weeks as the new acquisition begins to fade into the background of life as time marches on.
adding heat to the cabin using Climate Control automation when the ICE is not running, never impressed me either. I use a regular safety switched space heater before leaving on a trip, if I really want heat in the cabin when it starts getting really cold. as always YMMV

 

Have the Toyota dealer check your A/C system; since your running a heat pump. You may have a slow seepage leak in the system and I believe there is a TSB for that. The leak is at the O-rings that connect to the condenser, in front of your radiator. Look at those connectors for an oily dirty residue around the connector and bolt. If your levels are low; the cabin won't heat or cool as well as it should. Of course you know, as it get colder, the heat pump becomes less efficient and your engine will fire-up to heat the cabin.

Hope this helps...

 

I don't have techstream so I can't see the actual TSB issued by Toyota.
A ton of hits from search though.

edit Thanks @BiomedO1

 

BTW, when I said replace the coolant, I meant the engine coolant of the radiator. I am not aware of any refrigerant service mentioned in the manual. Still hard to believe it needs to be replaced or filled, but @BiomedO1 commented a good point if it is related to the refrigerant leak, then it would explain the loss of heating or cooling efficiency.

 

The Prime will blink the Temp gauge on the dash for 5 to 10 seconds when first put into Ready mode, at either 2 or 3 degrees C, and there are major changes to the way the car behaves below those temps. We all watch as temps start to fall in the fall, which big changes are going to get the most post counts. So far this year it's The ICE starts up when it's Cold even in EV mode.

Heat pump NOT providing cabin heat in temps below 37 F / 2 or 3 C, is NORMAL. again as always YMMV.
Pre Conditioning adds other values to cold start trips, besides the side effect of sometimes being able to add heat to the cabin.

 

This all sounds normal to me. Heat pumps are pretty inefficient below freezing, and the colder it is the less efficient they are. That's why the ICE starts up when the temp drops in order to make heat. Bottom line anyway is that you're wasting energy trying to make heat with a heat pump in the cold, might as well just run the ICE.

 

As suggested, my experience with PP is that the heat pump in winter is useless. Especially on shorter than 30 min morning commute. I could never get the cabin temperature to get more than 5F higher than the initial temp. When I was commuting daily, I almost always started the car in HV mode as soon as I get in the car. From my experiments, I have learned that the HV and CHG mode efficiency is very close, so I plan to use CHG mode in the morning commute to get constant heat and save the EV mode for the afternoon.

 

grumpy - heh I've been wearing summer riding gloves the last few nights, even though I don't really need them yet.

dress appropriately (bundle up), open window(s) slightly to remove window foggy.

 

Amen! While we don't have such bone-chilling temps here, the heated steering wheel AND heated seats do make it a lot more bearable in our Southern New England winter weather.