Ok Guys, Please put your thinking caps on !! We are at our wits end. Are you ready….Ok here we go…
We have a 2013 Peterbilt…Paccar MX13. Truck runs great but have been having an issue when I turn the A/C on. The oil pressure spikes and coolant temp goes down. The Peterbilt engineers have been troubleshooting for days and days. They even changed the ECM, EGR valve, front wiring harness, oil pressure valve, oil cooler, thermostat, turbo speed sensor, heater blower motor, Heater Control Head and tested the ECU.
The check engine light is an EGR control valve.
Now they are thinking it’s a ground wire or common wire….
Has anyone ever heard of this issue? Would appreciate any ideas or suggestions !!!