My check engine light came on in my 2003 Chevrolet Impala LS so I took it to Auto Zone and they use the OBD on it and turn off the check engine light and said its my Knock Sensors so I need to know should I take it to my dealer for servicing.
To begin with the knock sensor being bad will not make your engine start to knock. Its a sensor the computer uses to monitor the performance of your engine so that it can adjust your timing as needed. I would recommend that you get it checked out as soon as possibile. But stay away from the dealer unless you can't find a good local repair shop. This is a fairly simple repair, and a local shop can handle it no problem. One other side issue, you say they turned off the light?? If that is the case, did the light come back on?? If it hasn't come back yet, your wasting your time taking it anywhere. When autozone reset your system they erased all the diagnostic data that the repair shop would use to correctly diagnose and fix the vehicle. Wait for the light to come back on, if it doesn't, then it was probably a piece of dirt on a sensor. Also keep in mind if / when the light is on, the system reports that there is a problem in the knock sensor circuit, but you may not need a new sensor, it can be a wiring issue, a bad connection, or sometimes a problem with another related component.
Knock sensors? That could mean that your engine could start knocking soon, if it does, then you will need a new engine. So have your dealer look at it and tell you what's wrong, but if you dont want to spend alot of money on the problem, dont have the dealer fix it. If you have your own mechanic, let him/her do it.
The knock sensor allows the engine to advance the timing for maximum performance and fuel economy. These are not the easiest things in the world to replace, so if you still have a warranty this would be the time to get it fixed.
