P0496 Chevrolet -

Question

I replaced the canister purge valve solenoid and bank 2 sensor 2 (closest to front bumper) o2 sensor on a 09 malibu 3.6L. Still have the p0496 code. Can this create the p0157 (which at one point i had) code as well? I think I wasted money replacing the o2 sensor (first thing I did, then purge valve). I thought i solved it by testing the purge valve because on the purge end i felt a vacuum plus rattling loud. What are some home tests I can try for diagnosis?