Low oil pressure code on my 2021 ford f150 2.7. I swapped out the sensor, no luck. Ran a multimeter to the harness for the sensor. Measured in at 5v ( i think that is normal) went to harbor freight purchased a gauge plugged that into where the sensor goes. Idle at 40 psi but when i gave it gas to 3.5k rpms it shot up to 95psi Truck is in limp mode as of now. I tried to reset the pcm by disconnecting the battery, still nothing. Truck is gonna go into ford for a diagnostic just seeing if there is anything i can do before i take it in since they said wait time of 1/2 weeks just for them to see whats wrong with it. Truck has 65k miles i did the oil change as well in hopes something was wrong with the oil filter nothing came of that either. I should state i took my whole front end apart while waiting for my paint matched bumper to come in and threw raptor 37” ko2’s on. Truck was ok then it threw a bypass valve code. Left it parked then when i moved it up to swap my bumper on once it came in i got the oil pressure light.

 

Since you put a master gauge on and have verified you have good oil pressure my next step would be it's either a bad sensor, wiring issue, or even a bad connector. The easiest next step would be replacing the oil pressure sensor and clearing the codes with a code reader or forscan. If you still have the code and low oil pressure problem then it could be a wiring issue, corrosion, chafed... Oil pressure sensors typically have 3 wires, I don't have the diagram in front of me right now but youll have a 5v power source, a ground and a signal return. You can check the +/- to make sure they're good using a multimeter and a incandescent test light for the ground to act as a load test with the alligator clip on the batter + and the test light end on the sensor ground. If it's bright the ground is good.

 

I have set up the multimeter already and was getting a 5v reading. How would i go about checking the other connectors and for corrosion?

 

Do you have continuity in the wiring harness to the ECU?