Q: P0380

The glow plug wire harness is not the entirety of the circuit. The circuit fault represented by P0380 could arise in the wiring to the harness that you replaced, including the ground connection. To determine the integrity of the remaining wiring and terminals requires voltage drop testing. Mere continuity, as reflected in ohmmeter tests is not enough. Also, check to see if your application uses timers or a control module as faults there can account for the code. That information will be on the Factory wiring diagram. If you continue on with the diagnostic you have performed thus far, you will find the circuit resistance that is causing the code to set. It doesn’t take much resistance at all to create a 10% voltage loss, which is the threshold at which the code will set. If you want the remainder of the diagnostic performed by a mechanic, please request an an electrical component/circuit diagnostic and the responding certified mechanic will get this diagnosed and resolved, right at your location. If you have further questions or concerns, do not hesitate to re-contact YourMechanic because we want you to make the most of your repair dollars and help you to get the best possible results.