Wont Start

I have a 94 mack ch 613 that just died. The code was high voltage at the rack sensor or shorted. The sensor is in the inj pump so the pump was replaced with a reman. The code is still there and wont start so we swapped ecm and bosch module logged same code. Unplugged firewall connector and the code stays the same So something else is setting the code but I'm at a loss. I've pulled all the fusees one by one and no change. Unplugged all the sensors one by one no change other then setting other codes that will clear.So any input on this would be great before I pull the rest of my hair out.