Mack trouble codes

[Rfoster]

This is my first Mack I’ve had peterbuilts and kenworths all with Cummins motors so just a learning curve 

[Joey Mack]

very good...  no sweat....  there are so many people here that will help you, myself included..  the truck you have is a good one. the engine you have is pretty good too.  "V" had  a good idea about fuel pressure...  I always talk about ground wires..  so here's a small lesson...   open the fuse cover on the right dash board, look at the cab frame and you will see a 10mm bolt head, its a ground, clean all of the eyelets and the frame, do the sane thing behind the instrument cluster at the bottom left corner of the cab frame is another 10mm bolt head, clean it,  then go to the firewall below the left windshield and clean the ground breaker contacts. it's the black relay next to the starter relay, it has black wires going to it, the left side of the engine midway in front of the starter, is a 15/16" headed bolt, remove it and clean all the eyelets and the bolt and the block, it is a main ground, then follow the cable to the frame 1 foot away and clean the frame ground, its 15mm bolt head, its behind the steer tire... get these grounds cleaned really good, and start over, also check fuse #40 in the fuse box under the hood by the steering shaft, make sure it is clean and tight in the socket and 25-30 amps. these are some basic checks that I do even if a 9-2 code is not present...  good luck, Jojo

[Rfoster]

Thank you for that info that gives me a place to start!