Matt.2408

So there has been issues with my dad's car before, when it was bought there was a problem with the engine, had it replaced but the new (used) engine didn't come with everything so some stuff including the camshaft positioning sensors were moved over from old engine. Then for weeks or months there was codes P0016 and P0017. So changed out a sensor on each bank and check engine light was gone. Then after some time codes P0012 and P0014 would come and go on it's own, I I read up on it a bit and found out it might be the camshaft adjusted magnets on bank 1 which is easier to replace than bank 2. I got some Mercedes OEM sensors and the car seemed to ride better, better throttle response so I cleared the code and it was good for a like 2-3 days. Then one of the codes came back P0012, which it's "Camshaft Position 'A' Timing Over-Retarded Bank 1" not sure if the "A" is the intake or exhaust but I believe on the exhaust sensor the plug that goes into the sensor had oil on it. Could it be that the harness to that sensor is bad? What else might I check?