Ice won't start for heater

Here's a quote from another thread:

"Gen 2 and 3 Prius have some supplemental PTC heaters (Electric Heating Elements for those cold mornings). ...the ICE does NOT need to run to provide requested cabin heat. It only needs to run if the engine coolant temp is too low for the given amount of heat demanded. I've confirmed similar behavior on other Toyota/Lexus hybrids and the Altima Hybrid"

Learn more by reading the thread: Explaine how the heater works | PriusChat

 

If you're having problems with not enough heat, the first step seems to be confirming the condition of your electric elements, than looking at ICE coolant system that's used for additional heating.

 

It does seem odd to me that the engine isn't being run more when there's a demand for heat. Compared to the heating capacity of the coolant-fed heater core (5300 watts), the PTC elements (about 700 watts total when fully in play) are really just a supplement while the engine warms up, and a fairly puny one at that. (I could put it this way: I've never been able to feel anything I'd actually call "heat" coming out of the system, on a cold morning, with only the 700 watts of PTC input before the engine is warm. The one time you can really even notice they're doing anything is if you need to run the front defog while the engine's still cold. Then they do at least make enough difference that you can tell they're working.)

I might pull up the ECM data list, or the HVAC data list, in Techstream, and look for any signal that represents a heat demand from the HVAC to the ECM. (I don't remember offhand whether I've seen one, but if this were my question, it's the first thing I'd check for.)

Once the engine is at least partly warmed up, then yes, it will shut down, and simply keep pumping the hot coolant through the heater. It will cyclically restart, when the coolant gets cool enough, to heat it back up, and shut down again. But it seems mine will often start the engine right up if I ask for more heat, unless it has just recently shut off and the coolant is quite warm still.

-Chap

 

If you have/could get a digital temperature gauge so you can record cabin temp... Or I've been told Techstream can give you this data... Point being getting verified temperature data is key, especially this time of year because the first cold days in Fall always feel way colder due to our bodies taking time to adjust to first stages of the season's winter weather.

 

I found this interesting tidbit in the shop manual this morning regarding the PTC heater. I didn't know these cars had them, looks like the PTC heat comes out of one duct.

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how long have you owned your car jamie? is this a new occurrence, or ongoing?

it could be that the engine has warmed up, but you have a different problem like a thermostat or coolant valve

 

Yes, Techstream shows the temperatures, humidity too. I thought you had a copy of Techstream?

 

I find my 2010 engine only runs to supply heat IF the heat control is on auto!
If I have the temp on 70 and the fan on 3 or 4 bars and the control not on AUTO my ice only runs to supply energy after the cold engine start up.

 

that is very odd, i have never used auto. plenty of heat. the temp gauge is poor though. i have to turn it way up, or way down to get it to change much.

 

Techstream is basically what the dealer uses to figure out what is wrong with your car. You use it with a device that attaches you to the OBD port in your car.

It’s not expensive but you do need an old laptop or something.

V13.00.022 MINI VCI Single Cable Supports Toyota Diagnostic Software

 

Because this is your first Winter in this car, do you know anyone with a similar car so you can compare? As for what the "temp" feels like, that's not an accurate way to measure, especially when its the first cold weather of the season you're talking about. You can buy a digital clock with a thermometer on it for $5...

If I had to guess, your car is fine and your expectation for more heat may not be possible to achieve... But before that is the case, we need to figure out if this ICE not running with heater on is consistently happening? Clearly, sitting in you car and not driving anywhere when it's super cold out and you just started the car is one thing. But your ICE does run, it's just an issue of when it runs, which is highly variable depending on the vehicles needs. Looking into heater performance after you've been driving for 20 minutes or longer is what matters most if there's a problem that needs to be verified.

 

Check your coolant level in the radiator, not the overflow bottle to see if the radiator is full. Sometimes a low coolant level causes that.
Just don’t open it when it’s hot. You could get burned.

 

Didn’t someone here mention once that if you don’t bleed the cooling system the heat does not work?

 

If that's the case, that would explain my own concern with my car? Hope someone confirms that's true!

 

Check around the belt driven water pump to see if the leak is there.