Turbocharger Recirculation Valve Audi A4. The recirculation valve is operated from the depression in the air inlet upstream of the turbo and downstream of the throttle valve. When the throttle valve is closed and the pressure in the inlet drops the valve opens and air from the discharge side of the compressor is diverted back into the inlet of the compressor.
Battery power comes to the valve from the fuel pump relay and the ECM controls the ground to the valve. I have a 2007 Audi a4 20 turbo with a p0299 code. These valves are also fully serviceable.
2017 Audi A4 Quattro L4-20L Turbo.
The recirculation valve is operated from the depression in the air inlet upstream of the turbo and downstream of the throttle valve. These valves are also fully serviceable. Forge claims a greater flow rate than the OEM Bosch Valve and a unique compact design for greater clearance. Gives a horsepower boost and reduces turbo lag for little money and effort of installation.