My check engine light came on and this is the code I got P0121 OBD 2 code

First of all, have the fault codes been proofed out. Has it been diagnosed by a Technician. I understand you have codes and what the definition it says, but that doesn't mean the fault is with the component mentioned. It's just a possible cause or the fault is in the circuit pertaining to the component. The fault needs to be proofed to be able to do the proper repair. It could be as simple as a bad connection, wire, ground, or wrong information the computer has received from another source. Have it tested first.