P1416 indicates a fault with your Yukon's Secondary Air Injection (AIR) system on Bank 2 (engine side on which cylinder 2 is located) of the engine. Your Yukon's engine is designed to allow fresh air to mix with the air/fuel mixture in order to lean the fuel mixture and allow the catalytic converter to heat up faster during cold start-ups. The system triggered fault code P1416 the the PCM (Powertrain Control Module) cycled the AIR injection system ON, and the O2 (oxygen sensor) did not show an increase in air flow. The problem, more than likely, is a defective check valve. Also, check for damage to the AIR injection plumbing system on bank 2 of the engine. Look for pinched, kinked, broken or restricted AIR pipes, hoses or fittings.
The find the AIR injection check valve, locate Bank 2 of the engine. When sitting in the drivers seat, Bank 2 will usually be located on the passenger side of the engine. Verify this before attempting to locate the check valve. If you find that the valve is defective, we recommend replacing both Bank 2 and Bank 1 at the same time. To find the valve follow the metal tubing from the exhaust manifold and follow it to a black valve. This will be your Yukon's AIR injection system check valve. The valve will lead to the air pump.