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Auto Grade Braking question

grndprx18

By grndprx18
in Troubleshooting & Recalls

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grndprx18 New Member

grndprx18

Posted
Posted

Hi everyone! I am new to the forum and I just bought my first new truck ever a few weeks ago. Its a 2015 Silverado Crew Cab Z71. For the first few weeks every time I went down a hill, even a very gentle slope I would see a message pop up saying auto grade braking and my rpms would climb from the transmission downshifting. It did this for the first 3 weeks after I bought it (around 450 miles of driving). Now for the last 3 weeks I have been driving it (up to 1100 miles) I have yet to see the message come back and the transmission never downshifts even going down steep inclines on the highway unless cruise control is on. I live in the east TN mountains so I drive through a lot of terrain level changes daily. Did I manage to disable a feature on the truck? There is no warning lights on the dash. Hopefully its nothing but I thought I would get the forums opinion.

 

Thanks so much!

 

newdude Senior Enthusiast

newdude

Posted
Posted

Unless you have held the tow/haul button in for 3-5 seconds, it should still be active as it is active with every key cycle.

Normal Mode Grade Braking

If equipped with a gasoline engine and an automatic transmission, Normal Mode Grade Braking is enabled when the vehicle is started, but is not enabled in Range Selection Mode. It assists in maintaining desired vehicle speeds when driving on downhill grades by using the engine and transmission to slow the vehicle. The first time the system engages for each ignition key cycle, a DIC message will be displayed. See Transmission Messages.

To disable or enable Normal Mode Grade Braking within the current ignition key cycle, press and hold the Tow/Haul button for five seconds. When the button is released, the requested mode change is made. A DIC message displays. See Transmission Messages.

 

AND

 

ACTIVATION

  • Normal mode powertrain grade braking defaults to "ON" after each ignition key cycle.
  • To disable or enable all grade braking within the current ignition key cycle, press and hold the Tow/Haul button for three seconds.
  • No grade braking is available in Range Selection Mode (Manual Shift Mode).
  • For grade braking to activate it requires the driver to apply steady brake pedal pressure to maintain desired speed while driving on a downhill grade. The vehicle's modules monitor the amount of brake pedal apply, vehicle deceleration rates, and other factors to determine if normal mode powertrain grade braking is necessary. When the feature activates for the first time that ignition cycle, the DIC will display "Grade Braking On" or "Grade Braking Active" and you will notice the transmission down shifts and engine RPM increases. At this point, if the brake pedal is released the transmission will hold the current gear. If additional engine/transmission braking is needed to help maintain desired speed, reapply steady brake pedal pressure and additional down shifts may occur.
  • Normal mode powertrain grade braking will have a less aggressive transmission down shift schedule than Tow/Haul mode powertrain grade braking.
  • Grade-braking can be exited by depressing the accelerator pedal.

 

grndprx18 New Member

grndprx18

Posted
  • Author
Posted

Thanks so much for the quick response. I have done the 3 second thing to toggle it on and off while parked one day to see if that helped but it didn't. I guess its something I can ask the dealer about when I go in for the first oil change. I may disconnect the battery today when I get home and see if a computer reset helps.

 

Unless you have held the tow/haul button in for 3-5 seconds, it should still be active as it is active with every key cycle.

 

AND

 

Rkaroll953 Enthusiast

Rkaroll953

Posted
Posted

wow i have only seen that in tow haul mode. i wonder if my truck will do that in just normal everyday driving too.

grndprx18 New Member

grndprx18

Posted
  • Author
Posted

wow i have only seen that in tow haul mode. i wonder if my truck will do that in just normal everyday driving too.

According to the owners manual and GM sales brochure it should work in any 13 or newer trucks with 6 speed auto and v8.

redwngr Senior Enthusiast

redwngr

Posted
Posted

"For grade braking to activate it requires the driver to apply steady brake pedal pressure to maintain desired speed while driving on a downhill grade. The vehicle's modules monitor the amount of brake pedal apply, vehicle deceleration rates, and other factors to determine if normal mode powertrain grade braking is necessary. "

 

 

 

With cruise engaged, it will try and do the same thing -- maintain the desired speed.

 

 

Steady brake pressure OR the cruise setting will tell it the desired speed to maintain.

 

 

First time my 2015 downshifted on a long grade (I had cruise engaged) it surprised the %$#% out of me.

grndprx18 New Member

grndprx18

Posted
  • Author
Posted

Hi everyone. Just wanted to let you guys know I did disconnect the battery for 30 min or so last night and on my way into work the grade braking started functioning again. I hope it lasts! Just thought I would give an update. Thanks again for all the quick replies. I look forward to being an active member on this board. Thanks again!

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