2003 nissan xterra knock sensor problem also

my check engine light is coming on on my xterra (similar to other question). I took it to auto place to get diagnosed it read knock sensor and gas cap. can you give me advise on my problem? thanks CJ

Should read knock sensor or gas cap.
Gas cap wasn’t tightened properly. Common error.

kid told me that my gas cover might need new gasket??? and then I would have to fix both problems before the check engine light would go off-

There’s two different problems.

There’s a small leak in the vapor recovery system. This leak could be the gas cap or another leak somewhere else in the system. To check the cas cap, smear a small amount of petroleum jelly around the seal for the gas cap and reinstall it. if the same code returns, the problem isn’t with the gas cap but somewhere else.

The knock sensor is mounted on the engine, and detects if engine ping/knock is occuring and the computer makes adjustments to eliminate the ping/knock. The code for this usually points to a circuit problem. This could be the knock sensor or the wiring to it.

So you need to have the vapor recovery system tested for leaks, and determine if the a problem with the knock sensor is with the sensor itself or the wiring. Otherwise that Check Engine light will be on all the time. And you don’t want that.