My 2015 Hyundai Elantra dies when passed to reverse + engine light P0449

Question

I have a 2015 Hyundai Elantra. 90000 miles. It dies when passed to reverse. the engine light comes on: P0449. I changed the evap vent valve but still it keeps doing it. I read that "Usually when you shift into reverse and engage the brake it will cause the engine RPM to drop; as it's creating a load against the transmission and the engine. If the engine stalls, it may be caused by a faulty idle control valve, bad O2 sensors, or clogged fuel injectors." How can that be linked to the vent valve?