“Heater Performance Mode Active” Message / Extreme Cold Outside

[Micahsd]

Here’s something strange. Twice now on days when the high temp was 0 degrees or less here in Iowa, when I go to remote start my ‘21 Tahoe and later get inside it the dash will display the message “Heater Performance Mode Active”. Anybody know what that means? I can’t find anything in the manual about it.

A few other observations about when it’s this cold. The magnetic shocks/suspension is real stiff and the steering wheel turns hard like I’m driving a vehicle with no power steering. Guessing all of that is normal since when it gets up into the 20’s it’s a much better driving experience.

Attached is a photo of the message that appeared.

 

[Pro299]

The Dmax has a valve to prioritize warm-up. Has something like that been added to the gassers?

 

[Micahsd]

The Dmax has a valve to prioritize warm-up. Has something like that been added to the gassers?

Something like that would make sense.

I’ve only seen it on these two 0 degree days. We’ve had some other cold days in the low single digits and that message never displayed.

 

[TrueAt1stLight]

Interesting message! Living in the Twin Cities, my 21’ Yukon Denali hasn’t really seemed much-affected by temperature. I have an air-ride equipped Vehicle and haven’t really noticed much impact due to temp changes. I do keep it garaged so perhaps that could be the difference.

 

[Pertzbro]

All vehicles are stiff when it's this cold. Wifes 2014 explorer, my 2015 ram. Steering, seats, suspension, etc. I'm in NW Iowa. seeing below 0 rather regularly. My ram has seen -25 in Colorado mountains. I tore out my air suspension in the Ram due to frequent cold weather problems. No air suspension ever again. ever. $1,500 for the option only to be torn out 5 years large for $2,800. Rode amazing when it worked though.

 

[Jpilot64]

Here’s something strange. Twice now on days when the high temp was 0 degrees or less here in Iowa, when I go to remote start my ‘21 Tahoe and later get inside it the dash will display the message “Heater Performance Mode Active”. Anybody know what that means? I can’t find anything in the manual about it.

A few other observations about when it’s this cold. The magnetic shocks/suspension is real stiff and the steering wheel turns hard like I’m driving a vehicle with no power steering. Guessing all of that is normal since when it gets up into the 20’s it’s a much better driving experience.

Attached is a photo of the message that appeared.

I received something similar about a day before I got a solid check engine light…. Also near zero temps outside of Pittsburgh.

I don’t remember exactly what the message was. I’ll post when I get it back from the dealer next week if it’s applicable.

 

[eyebereej]

This is what I found on the interwebs,

Heater Performance Mode (8-Cylinder 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.

 

[Jpilot64]

This is what I found on the interwebs,

Heater Performance Mode (8-Cylinder 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.

Yeah, she’s a LM2 duramax though

 

[Jpilot64]

I received something similar about a day before I got a solid check engine light…. Also near zero temps outside of Pittsburgh.

I don’t remember exactly what the message was. I’ll post when I get it back from the dealer next week if it’s applicable.

Started her up this morning, after being -5 degrees F after having the block heater plugged in for 8 hours overnight, no check engine light illuminated any longer.

 

[MAYukoner]

Do all come w heater block?