I put in a new dealer-purchased engine in my 2007 Suburban about 6 years and 65k miles ago. The engine runs great, no issues. The car itself has about 250k miles on it and has some quirky electrical issues. Sometime the windows don't go down or the doors fail to unlock/lock. I have replaced the BCM (properly coded) but the issues persist.

A few months back my oil pressure sensor was providing very erratic results. Sometime low and triggering the shutdown engine alarm, sometimes very high but never accurate. I have since replaced the sensor and it provided accurate readings for a very short time and now it is stuck on zero oil pressure and has a P0523 code. My sense it that all of these issues are tied together. I have cleaned and reground all of the places that I know about to no avail. I am in California and need an emissions inspection but cannot pass due to the CEL and code.

Does anyone have any insight into what may be happening? Maybe an electrical short or a loose/dirty ground? Any thoughts or troubleshooting steps would be appreciated. Thank you in advance.

 

Your windows and door locks problem is likely broken wire(s) in the drivers door jamb.
Your oil pressure problem is either a bad oil pressure sensor, hogged out terminals in the sensor connector or an open ground circuit for the sensor.

 

I'd replace the oil sender again. If you really had zero oil pressure, your engine would've been ruined in just a few miles or less.

 

Take out the sensor again and remove that useless little plastic screen from down in the threaded hole. They constantly get filled up with sludge.

 

Some seem to have a plastic screen down in there and some don't.