Power steering went out when I pressed my brakes.

Power steering went out when I pressed my brakes got off the road still no steering turned off truck started it no steering gave it throttle and it came back also felt like I lost some breaks truck is a 2011 dodge ram 2500 mega cab diesel also rear view auto mirror darkens at random for do reason and tire sensor sais low even tho tires read 70 psi on the in cab monitor also check engin light reads and code is p0408 also have huge mileage loss from 19mpg to 11mpg