Is fuel sensor covered under power train warranty?

Blonjuan44

Engine light is on, we had a mechanic get the codes. The car is a 2011 Buick Enclave with 99,100 miles. Does this car have a 100,000 warranty, are the following two code items covered?

P0451 Evap Ctrl sys pres sensor and
P0495 EVAP SYS HIGH PURGE FLOW?
Would this be solved simply by adding fuel dewatering additive?

If not please provide estimate and do people generally bring in at 99,100 to check for any warranty items for over 100K?