One of the injured, Kayden Basil French, was sitting in the passenger seat of the silver 1997 Mitsubishi Lancer Evo 4.
He suffered "extremely serious injuries" which he was still recovering from and would be for some time yet, police said.
Walker suffered a knock to the head and the other injured passenger, Stephen Edwin Palmer, was sitting on the right-hand side of the car.
His injuries included two spinal fractures.
The Serious Crash Unit gathered evidence from the scene and conducted an investigation into the crash.
Farndon Rd has ditches, a number of trees and narrow shoulders.
Walker was remanded on bail and will return to court on February 23.