VW Jetta Wagon Check Engine Light

I took my car to a local auto shop and he said that it's either of the 2:

1. Manifold absolute pressure in barometric pressure circuit range or performance problem / code 16490
or
2. System too rich at Idle bank 1 / code 18620

My car is under 3 years old, and on a lease which is up in 3 months. Do you know if the dealer should cover this or if I should just get it repaired at an auto shop nearby?

Thank you,
Lisa