false oil pressure signals
 

My 2003 chevy Silverado k2500 (6.6L) will not pull my travel trailer. It works ok until the trailer is attached. After 30 minutes or so of pulling, the oil pressure gauge drops to zero and the computers kick into reduced power mode. I had it checked by three diesel shops who indicate there is no actual reduction in oil pressure. The codes that are stored are PO522, PO641, and P112. The oil sending unit has been replaced, the fuel filter changed, and the injectors serviced. Any idea of where to look for repair?

move this to the LB7 duramax section and you will get a better response

what was the actual oil pressure with a manaul gauge on it?some of tese trucks have had harness issues and some had drivers going out the scm

i had the cluster replaced and the oil sending unit was replaced twice. I got three low oil pressure messages today after driving 70 miles. What else might it be?