Hello I got a Freightliner 2012 I got a code fail 17, , espn 100 and ENG or (enc 1) 1

Before all this my truck was having some problems low oil pressure I fixed it , something was broken under the oil pan, new parts was installed ;right after I get all this code please for the love of God help me

 

I appreciate your respond ; oil pressure it’s 50 normal and we installed new 5 rings also just the speedometer Needle drop from 69 to 15 but I never loss speed, RPM NEVER DROPPED?!!?

 

Thanks for all the help , whenever I start my truck am hours oil pressure it’s over 50 and operating it’s just about 50 as well , I want to said also that I replaced this part , that was broke, after I replaced it and also new O rins the oil pressure it’s back to normal , but I never reset codes because I don’t have a computer don’t know if I should take other steps ??![GALLERY=]

 

Hello I appreciate it your help , check engine not on just the code eng1, spn 17 and oil pressure looks normal, if I unplugged battery could code reset!?

 

Please anyone HELP , I probably did 1000 miles after I repair the ther oil suction manifold , pressure can back to normal over 50 when I start truck no more check engine or stop engine ; so after all repair was running normally for couple days ; Is my third day running and about to park at house I get check engine this are the code eng1 , FAIL 17, SPN84 , FAIL 31, one eng light come on and the other one too , spn 4595210 , I drove truck for about 1 1/2 and parked anyone please help