I am on a volunteer fire department and we have a 2009 Rosenbauer Ladder truck. I do not work on big diesels very often so i am limited on my resources. So that being said we had a run a couple weeks ago and a stop engine light came on while we were heading to a fire. It had a code 556 excessive crankcase pressure. The truck ran fine and never set the code again after. So i replaced the crankcase filter cleared codes with a pro link. After that i went into data pids and watched the crankcase pressure and I thought it was high, 6.0 in h20 at 2,200 rpm no load 140 deg F goes to 0 inh2o not running and less than 1 in h2o at idle but i can feel pulsing air from oil fill cap at idle with my hand. My question is what is the set criteria for a code 556 and what is acceptable pressures. Thanks in advance.

Trevor Wenning
Technician
Wayne Oil
Fort Recovery, Ohio, USA