High Idle

[gSwift]

I've read a few things in the owners manual and saw a YouTube video of a Chevy 2500 that had the high idle feature. I have a pretty highly optioned 2500 AT4 Diesel and can't seem to get it to work. 

 

Anyone else have the feature and been able to get it to work?

 

 

[sdelam]

Set the parking brake, hold the cruise button down a few seconds and release. Works ok for me. Check your window sticker/ build sheet. Its  $200 option. The dealer should be able to set it up if you dont have it since its software only. 

[gSwift]

9 hours ago, sdelam said:

Set the parking brake, hold the cruise button down a few seconds and release. Works ok for me. Check your window sticker/ build sheet. Its  $200 option. The dealer should be able to set it up if you dont have it since its software only. 

Yeah I don't see it on the window sticker. I'll look into having the dealer set it up

[gSwift]

On 7/13/2020 at 8:11 AM, sdelam said:

Set the parking brake, hold the cruise button down a few seconds and release. Works ok for me. Check your window sticker/ build sheet. Its  $200 option. The dealer should be able to set it up if you dont have it since its software only. 

No rush, but if you get a chance can you take a picture of what its listed as on your window sticker? My dealer hasn't been much help. They keep trying to tell me that I don't have PTO and I keep trying to explain to them that's not what i'm referring to. 

 

They don't seem to understand that Elevated Idle, Fast Idle, and Power Take-off are all different features.

[sdelam]

12 minutes ago, gSwift said:

No rush, but if you get a chance can you take a picture of what its listed as on your window sticker? My dealer hasn't been much help. They keep trying to tell me that I don't have PTO and I keep trying to explain to them that's not what i'm referring to. 

 

They don't seem to understand that Elevated Idle, Fast Idle, and Power Take-off are all different features.

Honestly the only thing I have used it for is if I have to make a stop during a regen. 

[gSwift]

2 hours ago, sdelam said:

Honestly the only thing I have used it for is if I have to make a stop during a regen. 

Thank ya sir! Yeah I probably wouldn't use it often, or at all

[Colossus]

Regen only works based upon MPH not idle speed unless it is a commanded regen via the Tech-II tool. 

[sdelam]

On 7/19/2020 at 5:37 AM, Colossus said:

Regen only works based upon MPH not idle speed unless it is a commanded regen via the Tech-II tool. 

The high idle will help keep the exahust temps up though. I find it lets the truck finish the regen when I start driving again as oppsed to ending early and having the truck restart from a cold exhaust. Maybe its all in my head and I just need a reson to use the $200 option. Idk. 

[Dave mags]

I was told it can't be added when i asked my dealer last winter

The elevated idle will keep exhaust temps up in cold weather to prevent wet stacking 

I try not to just idle at anytime 

just shut it down 

also a no idle law in CT

 

 

[kylant]

my truck does not have that option.

however, the overnight temp the other day was down to about 35*. I remote started the truck. When I came out to it, it was definitely in a high idle state

[redwngr]

There are two ''increased idle 'different functions.  One is standard, the other is optional

 

In addition, the ecm will also sometimes adjust idle for alternator charging, ac compressor, high engine temp or in regen to keep exhaust from cooling. (and there may be other reasons....)

 

 

Elevated Idle  is standard on all the dmax's since 2004.5 LLY.  It needs to be enabled in settings, but then will  automatically engage if the correct conditions are met. It drags the torque converter to create additional load, to warm the transmission as well as the coolant.  

Since it has automatic engage it is great during cold weather when the truck is started by remote. I find that elevated idle will result in the highest transmission temps my trucks will have doing rural daily driver chores in winter weather.

 

Elevated Idle
The engine has a cold temperature high idle feature which elevates the engine idle speed from base idle to 1050 to 1100 rpm when outside temperatures are below 0 °C (32 °F), and the engine coolant temperature is below 65 °C (150 °F). This feature enhances heater performance by raising the engine coolant temperature faster.
To turn this feature on or off, see Vehicle Personalization 

 

[ Edit to add: My current truck will kick in elevated idle at temps higher than my previous ones. (an LLY and a LML).  Despite the 32*F indicated in the manual I find this one will kick in at temps somewhere between 38F and 42F on the dash display]

 

When the engine is started, it will slowly ramp up to the high idle speed after a delay of a few seconds up to approximately two minutes. For this method to work properly there must be no throttle or brake pedal faults.

 

The engine idle speed will return to normal once the following conditions are met: 

. Engine coolant temperature reaches 65 °C (150 °F).
. Air intake temperature reaches 0 °C (32 °F).
The high idle speed will be temporarily interrupted and the engine speed will return to normal if any of the following conditions occur:
. The brake pedal is applied.
. The accelerator pedal is pressed.
. The transmission is shifted out of P (Park) or N (Neutral).
. Vehicle speed is detected.
Once these inputs are removed, the engine idle speed will slowly ramp back up to high idle after the normal delay, if the conditions for engine coolant temperature and air intake temperature are still met. 

 

 

High Idle / Fast Idle

 

The other one is optional, and is operated by the cruise buttons - as in the video above.

Sometimes called High idle. Sometimes called Fast Idle.

 

Primary use if to keep accessories (and PTO is equipped) drive running faster.  Its'not intended create heat the way the elevated idle does. 

Fast Idle requires getting into the truck to activate.

 

2020 dmax manual calls it Fast Idle.

 

Fast Idle Control

 

If equipped, this system can be used to increase the engine idle speed.

 

Fast Idle control will be enabled when the following conditions are met:
. The parking brake is set.
. The transmission is in P (Park) or N (Neutral).
. The vehicle speed is about 0 km/h (0 mph).
. The cruise control Set switch is pressed and released for Preset

 

Fast Idle Speed (1200 rpm). Fast Idle control will be disabled when one or more of the following conditions occur:
. The cruise control Set switch is pressed and released. See “Cruise Control” in the owner’s manual.
. The cruise control Cancel switch is pressed.
. The brake pedal is pressed.
. The transmission is shifted out of P (Park) or N (Neutral).
. The parking brake is released.
. The vehicle speed is not 0 km/h (0 mph). 

 

 

Fast/High idle is slightly higher rpm than Elevated idle.  I've alway assumed it was to aid in identifying why the truck was not at 'normal' idle. 

 

When the truck is in regen, it will idle at higher rpm than normal - but not as high as these two functions.

 

Edited September 12, 2020 by redwngr

[Colossus]

The trucks will also jump up 200 RPM or so on a cold start, after about 20 seconds.  this generally lasts for about 30 seconds to a minute.  It aids in getting sensors and such warmed up.  I only notice it when the outside temps are below 50 degrees. 

[Brozat4]

On 7/19/2020 at 3:37 AM, Colossus said:

Regen only works based upon MPH not idle speed unless it is a commanded regen via the Tech-II tool. 

I know all of the documents state this, but is it 100% accurate? I have the "Fast Idle" option and I use it often as my truck is my mobile office and I idle alot at work. Sometimes while using the Fast Idle it definately smells like my truck is doing a regen when your near the back, even if I haven't moved it in a while. Thoughts?

[leverett.scott]

There are two ''increased idle 'different functions.  One is standard, the other is optional
 
In addition, the ecm will also sometimes adjust idle for alternator charging, ac compressor, high engine temp or in regen to keep exhaust from cooling. (and there may be other reasons....)
 
 
Elevated Idle  is standard on all the dmax's since 2004.5 LLY.  It needs to be enabled in settings, but then will  automatically engage if the correct conditions are met. It drags the torque converter to create additional load, to warm the transmission as well as the coolant.  
Since it has automatic engage it is great during cold weather when the truck is started by remote. I find that elevated idle will result in the highest transmission temps my trucks will have doing rural daily driver chores in winter weather.
 
Elevated Idle
The engine has a cold temperature high idle feature which elevates the engine idle speed from base idle to 1050 to 1100 rpm when outside temperatures are below 0 °C (32 °F), and the engine coolant temperature is below 65 °C (150 °F). This feature enhances heater performance by raising the engine coolant temperature faster.
To turn this feature on or off, see Vehicle Personalization 
 
[ Edit to add: My current truck will kick in elevated idle at temps higher than my previous ones. (an LLY and a LML).  Despite the 32*F indicated in the manual I find this one will kick in at temps somewhere between 38F and 42F on the dash display]
 
When the engine is started, it will slowly ramp up to the high idle speed after a delay of a few seconds up to approximately two minutes. For this method to work properly there must be no throttle or brake pedal faults.
 
The engine idle speed will return to normal once the following conditions are met: 
. Engine coolant temperature reaches 65 °C (150 °F).
. Air intake temperature reaches 0 °C (32 °F).
The high idle speed will be temporarily interrupted and the engine speed will return to normal if any of the following conditions occur:
. The brake pedal is applied.
. The accelerator pedal is pressed.
. The transmission is shifted out of P (Park) or N (Neutral).
. Vehicle speed is detected.
Once these inputs are removed, the engine idle speed will slowly ramp back up to high idle after the normal delay, if the conditions for engine coolant temperature and air intake temperature are still met. 
 
 
High Idle / Fast Idle
 
The other one is optional, and is operated by the cruise buttons - as in the video above.
Sometimes called High idle. Sometimes called Fast Idle.
 
Primary use if to keep accessories (and PTO is equipped) drive running faster.  Its'not intended create heat the way the elevated idle does. 
Fast Idle requires getting into the truck to activate.
 
2020 dmax manual calls it Fast Idle.
 
Fast Idle Control
 
If equipped, this system can be used to increase the engine idle speed.
 
Fast Idle control will be enabled when the following conditions are met:
. The parking brake is set.
. The transmission is in P (Park) or N (Neutral).
. The vehicle speed is about 0 km/h (0 mph).
. The cruise control Set switch is pressed and released for Preset
 
Fast Idle Speed (1200 rpm). Fast Idle control will be disabled when one or more of the following conditions occur:
. The cruise control Set switch is pressed and released. See “Cruise Control” in the owner’s manual.
. The cruise control Cancel switch is pressed.
. The brake pedal is pressed.
. The transmission is shifted out of P (Park) or N (Neutral).
. The parking brake is released.
. The vehicle speed is not 0 km/h (0 mph). 
 
 
Fast/High idle is slightly higher rpm than Elevated idle.  I've alway assumed it was to aid in identifying why the truck was not at 'normal' idle. 
 
When the truck is in regen, it will idle at higher rpm than normal - but not as high as these two functions.
 

Thanks for the info.

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[Mark Hulsey]

So can the high idle option be added at the dealership or does it have to be included from the factory? I have been to 3 dealerships that say it can't be added.