CAM Position sensor Wiring issue

MAGOOGOOLA

MEMBER
2012 FORD EXPEDITION
5.4L
V8
4WD
AUTOMATIC
172,000 MILES

I have Been having issues when truck is In reverse or under acceleration at low Rpm’s ( 1500Rpm and under ) and it starts running really rough.I plugged in my scanner and got 2 trouble codes, P0390 and P0394. I recently replaced Cam Position sensor B Bank 2 (Driver side) and still have intermittent issue happening. Engine will run fine for the most part only when such conditions are met. I believe this maybe an issue with wiring but not sure yet. Haven’t tested voltage or ground yet. Also don’t feel like taking apart the whole harness to look for a short if I don’t have to. Please let me know your thoughts, thanks !

Friday, August 29th, 2025 AT 10:42 AM

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
53,969 POSTS

I know this would mean the electrical portion of the camshaft sensors but what happens is you have a timing chain, camshaft actuator or oil control valve issue. I would make sure the engine oil is clean and full. These codes come up when the PCM expects the camshafts to be in a certain position while the engine is running which they are not there due to wear which gives these codes, does the engine make s light rattling sounds at idle? If so this is the problem.

P0390 - Camshaft Position Sensor “B” Circuit (Bank 2)
P0394 - Camshaft Position Sensor “B” Circuit Intermittent (Bank 2)

Here is the camshaft sensor locations if you want to give it a shot which are on the left side of the engine. Check out the images (below). Please upload a video of the engine idling so I can tell for sure in your response.

Image (Click to make bigger)