Diesel mobile mechanic in the Rosharon area

Anyone out there who knows there way around a school bus engine? I have a 98 International 3800 with the DT466e engine I've been trying to troubleshoot for a while. Was starting up and running great but all of a sudden won't start. Cranks and turns over though.

Getting trouble codes..

525: Injector driver circuit fault M

124: Injection control pressure signal out of range LOW

263: Oil/water lamp OCC self test failed

Any clues/advice/volunteers?

Thanks