Repair manual

SULEV 2.0L TFSI Engine
27
Secondary Air System
To reduce hydrocarbon emissions at the earliest possible
stage, fresh air is blown into the cylinder head exhaust
ports during the engine start phase.
The system is designed to rapidly develop pressure and
achieve a high delivery rate on activation.
The illustration below shows the components of the
secondary air system. The following components are new
to the system:
– Secondary Air Injection Sensor 1 G609
– Secondary Air Injection Solenoid Valve N112
The secondary air pump is positioned above the lowest
point of the pressure line system to prevent harmful
condensation from collecting in the pump.
If the system is functional, an excess pressure of
approximately 2.3 psi (160 mbar) will be achieved in
the pressure line while the engine is idling after a cold
start. Pressure acting on the sender increases with
rising exhaust gas mass flow, depending on how the car
is driven (high engine load). Pressure levels of greater
than 2.9 psi (200 mbar) above ambient pressure can be
achieved.
There is an elongated hole in the cylinder head below
the exhaust ports. Secondary air which flows through an
elongated hole is drawn directly into the exhaust ports.
The proximity of exhaust ports to the exhaust valves is
advantageous.
A secondary air reaction occurs immediately, generating
the thermal energy required to heat the catalytic
converter.
Overview of the Components
Secondary Air Bore
in the Cylinder Head
Intake Line
from Air Filter
Secondary
Air Injection
Sensor 1 G609
Pressure
Line
Secondary
Air Injection
Solenoid
Valve N112
Secondary Air
Injection Pump
Motor V101