Cat 312b Fault code 4204, 4302, 4208, 4209

I just bought a Cat 312b and the engine is pulling down during stick out or boom up. I pulled the active fault codes and they are as follows 4204 PWM sensor of pump delivery pressure is shorted to ground, 4302 mismatch data 2 between the alt and speed sensor, 4208 pwm sensor 1 is open circuit, 4209 pwm sensor 2 is open circuit. As for code 4302 I read no engine rpm so I have ordered a speed sensor. As for the other codes I have no manual to tell me what sensors they relate to. In the monitor under service code 21 which displays the higher of main pump delivery pressures it reads 4000 all the time and never changes. My guess there is a pump pressure sensor gone, would this throw these other codes? and if so how do I test it or them and where are they? Thanks for reading.