Excessive white smoke out of exhaust, especially with acceleration. smoke has a foul odor also. can hear a knocking sound in engine on deceleration (similar to bad wheel bearing hums), only does it if turbo is over 150-200 psi, but will do it every single time. 'drive to clean exhaust' displayed on dash. completed recommended drive cycle (over 30mph for at least 20 minutes, i drove for 45 mins) and message still appears. "wrench" symbol displayed on dash. per owner's guide the rtt displays when engine has defaulted to "limp-home" operation or when transmission problem has been detected.. the light comes on every time vehicle is driving now, and stays on entire time.
Ford f350 with 6.4l diesel had check engine light (cel) illuminate while driving. engine immediately slowed to idle (800rpm) and would not respond to throttle inputs. was not able to clear roadway and blocked traffic on busy urban road. dealer was "not able to find anything wrong", yet "performed calibration update on pcm". i was informed "this needs to be done as vehicle ages and sensors wear." reviewed owners manual and did not located maintenance interval for "calibration updates to pcm." i am certain this is an inherent pcm software code error leading to complete loss of engine operation. a dangerous situation on congested roadways. *tr