camshaft position sensor relearn?

It shouldn't need to have anything done other than changing it. What is the reason for changing it?

we got the error code that told us it was the B side,I don't remember the number we did this Saturday and right now I don't have access to the car
thanks

Do you know the actual code you have? Asking because many times it is not a bad sensor but either wiring or an internal issue with the cam phasers.

I don't know the code.

What are the symptoms other than the CEL being on?

Will send more info when I'm with the car in a couple of weeks. Thanks for the help.

No rush. We will be here.

Car is a Hyundai Elantra 2.0 Sel. The code is: P0017. Changed cam sensors & couldn't zero out code. Could it be the timing chain?

It could be but I doubt it because it is only the single sensor and no other codes. As such I would say to pull the exhaust cam VVT actuator oil control solenoid, be sure it isn't plugged with trash or sludge. If it isn't and the oil is clean then test the solenoid to be sure it operates. I generally just use a 9 volt batter but you can use the 12 volts as well, you just want to see if it works. If it tests OK then it is probably the VVT sprocket that failed and is locking the cam in the full retard position so the sensor sees the cam out of time compared to the crank. About the only repair is to replace the sprocket and if you are already there you might want to do a full timing chain replacement.