during the regen the carbon (soot) in the DPF is burned off to an ash. So..... in a properly operating system to me the question is. Is the white "smoke" unburned fuel or just the white ash from the DPF regen process. Under a reasonable highway load I wouldn't expect to see the ash as visible. But stop at a light, not much exhaust flow, ash is still being formed and give it some throttle and what may be coming out is just a pile of ash.
2015.5 Sierra Denali CC/SB/4x4 Stone Blue Metallic/Jet Black Interior
pinstriping by Bob Spencer AKA "spirit", undercover FLEX tonneau cover, color matched bug shield and vent visors, raintracker rain sensing wipers, X-treme coating bedliner, gm trailering camera system, coolant filter, Bilsteins, remote tailgate lock
04.5 LLY CC/SB/4x4 Allison Dark Green Metallic/Dark Charcoal Grey Interior
Webasto Hollandia Sunroof, Carbon Fiber Interior Trim, color matched bug shield & vent visors X-treme coating bedliner, Access roll top cover, Westin Step Bars, Lubrication Specialists Aux fuel filter, coolant filter, CAI, Michelin LTX tires, Manual High Idle Mod, Bilsteins, prodigy brake controller, raintracker rain sensing wiper controller, Remote autolocking tailgate, Reese Titan Class V hitch, Allison badges, Pinstriping by Bob Spencer, 4x4 decals removed, color matched door handles, 4 headlight mod, Homelink console.
97 Mercedes SL500, red with tan interior 97 Mercedes E420 sedan, royal indigo with grey interior 2001 KTM400EXC, 2011 Outback 295RE travel trailer