Heater do not work below -20 C.

My Nissan Leaf Forum

Help Support My Nissan Leaf Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

rullebulle

New member
Joined
Jan 29, 2024
Messages
3
Below -20 all heaters stop. Above -20 it works and the heat power indicator goes to 4,5 to 5 kW. Is there a setpoint for this?
 
Assuming pre-facelift Leaf?

All of the temperature sensors in this generation can only measure from -20C to +80C, so if the temperature is outside that range, it assumes a faulty signal and the A/C Auto Amp (heater and air con control system) refuses to operate.

On gen1 Leafs (2010-early 13), the heater will not work to protect the fluid pump, as the standard mixture in the circuit is only rated down to -20C, so it can freeze the fluid and damage the motor.
 
Assuming pre-facelift Leaf?

All of the temperature sensors in this generation can only measure from -20C to +80C, so if the temperature is outside that range, it assumes a faulty signal and the A/C Auto Amp (heater and air con control system) refuses to operate.

On gen1 Leafs (2010-early 13), the heater will not work to protect the fluid pump, as the standard mixture in the circuit is only rated down to -20C, so it can freeze the fluid and damage the motor.
Thanks

ZE1 A A03. -21 is the type. When was the pre-facelift ?
:)
/Olov
 
That's post-facelift. (your car looks like a Leaf you can buy today, not like the ones sold in 2010-2017).

I don't have full (searchable) service manuals for that generation, but since the Leaf hasn't changed much under the hood, I wouldn't be surprised if it still has the same limitations.
 
I looked in the '15 service manual, which is the one I have access to. It could be different than for your MY, but I don't think they changed the HVAC system much.
I couldn't find any references to the system shutting down at -20c ANYWHERE. The ambient temp sensor reads to -42C (-44F) as do most of the other sensors.
Eco mode reduces the output of the HVAC system, and I believe it will also shut it down when in "turtle mode". SO if you were driving in Eco or the turtle light was on, that may be why.
-20C is not cold enough to not drive the car.
I had mine out in -15F which is -26C and the turtle light was on until the battery warmed enough to raise the temp gauge out of the blue.
If Mux can find the info he has and print a screen shot of it I would be interested to read it.
Below a certain temp the refrigerant in the heat pump doesn't vaporize so the heat pump will be shut down, but the aux resistance heater strip should still function if other conditions are met.
Not saying Mux's info is incorrect, but spending a hour reading though the service manual section for the HVAC system I couldn't find it to confirm it. Here is a screen-shot of where it says they read to -42C
 

Attachments

  • Screenshot at 2024-01-30 09-19-39.png
    Screenshot at 2024-01-30 09-19-39.png
    158.1 KB · Views: 1
I looked in the '15 service manual, which is the one I have access to. It could be different than for your MY, but I don't think they changed the HVAC system much.
I couldn't find any references to the system shutting down at -20c ANYWHERE. The ambient temp sensor reads to -42C (-44F) as do most of the other sensors.
Eco mode reduces the output of the HVAC system, and I believe it will also shut it down when in "turtle mode". SO if you were driving in Eco or the turtle light was on, that may be why.
-20C is not cold enough to not drive the car.
I had mine out in -15F which is -26C and the turtle light was on until the battery warmed enough to raise the temp gauge out of the blue.
If Mux can find the info he has and print a screen shot of it I would be interested to read it.
Below a certain temp the refrigerant in the heat pump doesn't vaporize so the heat pump will be shut down, but the aux resistance heater strip should still function if other conditions are met.
Not saying Mux's info is incorrect, but spending a hour reading though the service manual section for the HVAC system I couldn't find it to confirm it. Here is a screen-shot of where it says they read to -42C
It's not in Eco mode.
 
I looked in the '15 service manual, which is the one I have access to. It could be different than for your MY, but I don't think they changed the HVAC system much.
I couldn't find any references to the system shutting down at -20c ANYWHERE. The ambient temp sensor reads to -42C (-44F) as do most of the other sensors.
Eco mode reduces the output of the HVAC system, and I believe it will also shut it down when in "turtle mode". SO if you were driving in Eco or the turtle light was on, that may be why.
-20C is not cold enough to not drive the car.
I had mine out in -15F which is -26C and the turtle light was on until the battery warmed enough to raise the temp gauge out of the blue.
If Mux can find the info he has and print a screen shot of it I would be interested to read it.
Below a certain temp the refrigerant in the heat pump doesn't vaporize so the heat pump will be shut down, but the aux resistance heater strip should still function if other conditions are met.
Not saying Mux's info is incorrect, but spending a hour reading though the service manual section for the HVAC system I couldn't find it to confirm it. Here is a screen-shot of where it says they read to -42C

The -42C value is a DTC fault value. In particular, it's the value corresponding to a sensor resistance value of 100kohm or more. The calibrated measurement range only goes between 0 and 100C on this sensor (see the table on HAC-329). The same goes for all other sensors; they have fault values outside of their normal operating range to check for shorted or open wires.

In your case though, it doesn't cause a DTC below -20C, it just refuses to operate under -20C to protect the heat pump. It can still measure these temperatures and know the wires aren't open or shorted.
 
Bad resistive heater, below the temp in which the heatpump will work. I've ran my Leafs in temps around -20F and it's heated just fine, using resistive heat.
 
Bad resistive heater, below the temp in which the heatpump will work. I've ran my Leafs in temps around -20F and it's heated just fine, using resistive heat.
Yeah, that is my suspicion also. It of doesn't register "out of range" until it drops below the -42C. The charts shown of temp graphs are just showing normal expected range. Nothing in the manual about heat shutting down once it gets colder than-20. In fact the heat pump transducer goes to -65F according to the manual.
Eco and "low battery output" due to temp, I could see it holding off running the heat strip and therefore not setting a DTC.
I spent more than an hour pawing through the manual, and found nothing to indicate it was "normal" to shut the heating system down in the cold.
I need to see it documented in print, where it says all heat function shut off below -20C before I'd accept that it.
 
My ptc heater doesn't work at -20 if the fan is set to high. I believe there's a service bulletin about it. I can monitor the current usage at this condition and see when the heater kicks in then turn up the fan
 
My ptc heater doesn't work at -20 if the fan is set to high. I believe there's a service bulletin about it. I can monitor the current usage at this condition and see when the heater kicks in then turn up the fan
If you have the SB please post it. The service manual wasn't very helpful on under what conditions the PTC heater was on and off.
Like JJeff. I had mine out in the extreme cold and don't remember no heat, I did have the reduced power (turtle light) on until the battery warmed up from use. I can see the PTC being restricted under those conditions, but can find nothing in the service manual to say that is correct.
 
Bad resistive heater, below the temp in which the heatpump will work. I've ran my Leafs in temps around -20F and it's heated just fine, using resistive heat.
**** you're right, cold weather leafs have the backup PTC heater that still works below heat pump temps.

It's a massive pain to replace.
 
Back
Top