2015 LML DenaliHD keeps moving after coming to a dead stop during redlight

[anre5180]

for the past week the truck has been having the following symptom:

Upon bringing the truck to a full stop at a red light and holding it there steady after a few seconds the truck keeps rolling slowly forward and I have to press another 2" down the break pedal to prevent me from hitting the car in front of me. After pressing a bit harder it does hold and no longer rolls forward.

no codes pulled, break system bleed and new fluid 1 year ago.

help! how can I troubleshoot with a certain degree of certainty... Master Cylinder? HydroBoost? I am not sure here

 

[Mike L.]

Put a professional scanner on the truck. Go into transmission data and pull up turbine speed sensor. At a stop it better read 0 RPM's. If not, your dprag is gone bad in the converter. Is it pushing through the brakes? If not, disregard my info.

 

[anre5180]

I have the AutoAgent2 from PPEI tunning with the app on my tablet i can see all the parameters you would normally see on a computer. it does show 0. see attach

 

[Mike L.]

Lookslike you have a brake problem.

 

[gmduramax]

My grandparents 4 runner would do that. Would be sitting at a stop, you would hear a thud almost like the ac compressor kicked on. Then it would roll forward. We just changed the brake pads and the rolling at the stop went away