120kw d5 2003, after changing the engine every morning when starting the engine the hell lamp lights up for about 5.sec. Causing an error for a few seconds. maintenance is ok. This is an oil pump or some other problem

 

do you have the correct weight oil and filter type? You may need to drop the pan to see if there's some debris or sludge clogging the pick up. Next is to check/clean the connection/wiring to the oil pressure sensor and consider swapping in a new sensor to get a trusty measurement.

 

Oil is ok Eneos A5,B5 5W30.I check first thinks.