PO340 CEL came and went, now what?
 

Leaving Los Olas the other night my CEL turned on, I scanned in the parking lot and it showed PO340. I get on here and find out it should be my alternator. I go buy one, then two days later the CEL light went off. Now I have a brand new alternator sitting in my house. Now what? Should I install it?

Also the car when the light was on during a system check said charging system was fine which I found to be odd...

http://www.obd-codes.com/p0340

A p0340 is a Camshaft Position Sensor Circuit Malfunction, not something with the alternator. I’d return the alternator. Good luck...

I would install the new alternator. Even though the DTC has nothing to do with the alternator in theory, that seems to be a sign of a bad alternator in the real world.

I'm going to update this so anyone else who had this problem can be helped down the road when they search this forum.

The CEL kept coming back and I'd clear the same code over and over. I finally changed out the alternator and the code is gone for good. I swore I could hear a slight whine from the engine compartment with the old alternator, but it was subtle. Changing it out was super easy, just make sure you have a 1/2 inch drive ratchet for the belt and a deep socket set to to get the bottom bolts off. (Might be able to do this with a wrench but a deep socket set is much faster) Took about 25 minutes.

Had P0340, changed alternator and code never came back.