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Heater Performance Mode Active?

2024Denali
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2024Denali Enthusiast

2024Denali

Posted
Posted

Having a hard time finding any information on this. We are in the middle of some record-setting cold, and upon startup the message “Heater Performance Mode Active” popped up on my screen. Can anyone tell me what this does?

Rob Mugs Enthusiast

Rob Mugs

Posted
Posted

I've never seen this and it's been pretty consistent 5-10F here lately.  Maybe because I am remote starting?  That said, a quick Google search says it's an elevated idle to help the drivetrain warm up a bit faster

calgator73 Senior Enthusiast

calgator73

Posted
Posted
17 minutes ago, 2020SilveradoCC said:

Having a hard time finding any information on this. We are in the middle of some record-setting cold, and upon startup the message “Heater Performance Mode Active” popped up on my screen. Can anyone tell me what this does?

Do you have a duramax?

This is from the HD duramax supplement.  

 

Heater Performance Mode (8-Cylinder Pickup Models Only) When cold weather conditions are detected, the transmission raises part throttle upshift points after the 1 (First) to 2 (Second) upshift to increase engine speed. This feature shortens engine and cab warm up times. When the transmission is in this mode, upshifts may be delayed. This is normal and does not indicate an operational problem

kodiakdenali Enthusiast

kodiakdenali

Posted
Posted

Just yesterday I was looking for a good ignition power source and saw somewhere in the fuse box documentation something referring to an electric supplemental heating device. I thought that seemed rather weird, then I just found this in the upfitter manual, maybe it has something to do with this? Looks like our trucks (at least some of them) have an electric heating element to help warm up the cabin faster when the engine is cold.

 

Electric Auxiliary Heater (C32)
Some models are equipped with an auxiliary electric
heater to assist in warming the passenger compartment
when the engine coolant has not sufficiently warmed to
operating temperature. The heater is a 12 V positive
temperature coefficient heating element located in the
HVAC case just downstream of the traditional heater
core. The HVAC control module will activate it when the
outside temperature is less than approximately 8°C
(46°F), the engine coolant temperature is less than
approximately 75°C (167°F), and the temperature blend
door is commanded to the full hot position.

2024Denali Enthusiast

2024Denali

Posted
  • Author
Posted
1 hour ago, calgator73 said:

Do you have a duramax?

This is from the HD duramax supplement.  

 

Heater Performance Mode (8-Cylinder Pickup Models Only) When cold weather conditions are detected, the transmission raises part throttle upshift points after the 1 (First) to 2 (Second) upshift to increase engine speed. This feature shortens engine and cab warm up times. When the transmission is in this mode, upshifts may be delayed. This is normal and does not indicate an operational problem

That's the weird thing - I dont. I have the 2.7T.

redwngr Senior Enthusiast

redwngr

Posted
Posted (edited)

 

 

Initial Drive Information

 

Transmission

 

Cold Operation (8-Cylinder Pickup Models Only)

When temperatures are very cold, the transmission will prevent certain operations to protect against damage. The information below shows shift range availability based on transmission oil temperature:
. All shift ranges available at −25 °C (−13 °F) or above.
. 2 (Second) and 3 (Third) shift ranges only at −35 °C (−31 °F) to −25 °C (−13 °F).
. 2 (Second) shift range only at −35 °C (−31 °F) or lower.

 

Torque converter clutch operation will also be prevented when air or transmission oil temperatures are below certain levels.
For areas where ambient temperatures are below −40 °C (−40 °F), use synthetic transmission fluid approved to Allison
Transmission specification TES-295. See Recommended Fluids and Lubricants 0 126 and Automatic
Transmission Fluid 0 95.

 

Adaptive Shift Controls (8-Cylinder Pickup Models Only)
The shift quality of a new vehicle may not be ideal because the Adaptive Shift Control process may not have determined the best settings for a particular shift or condition. Shift quality will improve with continued driving.

 

Low Traction Mode (All Models)
Low Traction Mode aids in vehicle acceleration on slippery road surfaces such as ice or snow. By selecting 2 (Second) using Range
Selection Mode while at a stop, the transmission will limit torque to the drive wheels to prevent slippage.
Chevrolet/GMC Duramax Diesel Supplement (GMNA-Localizing-U.S./Canada11354421) - 2018 - CRC - 10/10/17 

 

 

Heater Performance Mode (8-Cylinder Pickup Models Only)

When cold weather conditions are detected, the transmission raises part throttle upshift points after the 1 (First) to 2 (Second) upshift to increase engine speed.

This feature shortens engine and cab warm up times.

When the transmission is in this mode, upshifts may be delayed.
This is normal and does not indicate an operational problem.

 

 

Four-Wheel Drive (8-Cylinder Pickup Models Only)
When operating in 4 n (Four-Wheel-Drive Low), there is a very deep gear reduction.

The resulting shifts will feel exaggerated

 

 

 

imo, Kinda makes sense that the same Heater Performance logic would apply to the 2.7L T.

Edited by redwngr
eckseleven Enthusiast

eckseleven

Posted
Posted

My 3.0 showed this message this morning at -5F. I figured it was related to the high idle setting I enabled in the settings.

Moend Enthusiast

Moend

Posted
Posted (edited)

I started my truck this morning @ -24°F and didn't see the message, I have the 5.3 with 8spd - I don't warm it up in the morning start wait 1~2min then drive.

Edited by Moend
  • 2 weeks later...
Helo735 New Member

Helo735

Posted
Posted

I got this message in my 2019 2.7T last week when it was -25 where I was in Iowa. 

  • 11 months later...
JCoutts61 New Member

JCoutts61

Posted
Posted

I also have the 2.7T and asked at the dealership about this. I was told it activates the defrost mode when using the remote start in extremely cold weather, to assist in not having the windshield fog up when entering the vehicle.

  • 10 months later...
  • 1 month later...
Mark niceley New Member

Mark niceley

Posted
Posted

I get this message when its cold, the problem i have is that it seems to lower or cut out the heater in cab, but only when its really cold out 10 degrees or colder it seems.   is that normal ?

jashaw Enthusiast

jashaw

Posted
Posted (edited)

I had this a few times last year/get this message if I do not put the truck (2.7T) in my garage on very cold nights. It seems to operate just how the 8 cyl description says. Just raises the shift points some for a short time. 

Edited by jashaw

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