I just replaced the oil cooler/filter assembly on my sisters 2015 T&C, and afterwards, it set a CEL for P0523 - Engine Oil Pressure Sensor Circuit High. My first thought was bad or incorrect sensor (the new assembly came with new temp and pressure sensors). I cleared the code and was left with a permanent DTC, but no pending or active DTCs and no CEL. Today I went to look into it, and the code was back with a CEL, and again, after I cleared it, the CEL stayed away and only the permanent DTC was present. No pending or current DTCs. As a test, I unplugged the connector on the side of the head that contains the circuits for the oil pressure sensor, the oil temp sensor and knock sensors. Immediately on key on, I had current, pending and permanent DTC's for both the temp and pressure sensors. Clear the codes and they immediately return. Reconnect the connector and clear the codes and the pending and current codes do not come back.

This seems like an intermittent issue. At the moment, I'm suspecting the sensor, but is the harness that connects on the side of the head and fans out to the oil temp and pressure sensors and the knock sensors a common failure point? Could the sensor be intermittently going open? Anything else I should be checking, or should I just replace the new sensor with the original one?