Range Rover P38
17
EMISSION CONTROL
NEW RANGE ROVER
28
DESCRIPTION AND OPERATION
Secondary air injection (SAI) vacuum solenoid
valve
1. Vacuum port to intake manifold (via vacuum reservoir)
2. SAI vacuum solenoid valve
3. Electrical connector
4. Vacuum port to vacuum operated SAI control valves
5. Purge valve clip
6. Mounting bracket
The SAI vacuum solenoid valve is located at the rear
LH side of the engine, mounted on a bracket with the
EVAP system purge valve and electrically controlled
by the ECM.
Vacuum to the SAI vacuum solenoid valve is provided
from the intake manifold depression via a vacuum
reservoir. A small bore vacuum hose with rubber
elbow connections at each end provides the vacuum
route between the vacuum reservoir and SAI vacuum
solenoid valve. A similar hose with a larger size elbow
connector, connects the SAI vacuum solenoid valve to
the SAI control valves on each side of the engine via
an intermediate connection. The SAI vacuum solenoid
valve port to the SAI control valves is located at a right
angle to the port to the vacuum reservoir.
The intermediate connection in the vacuum supply
line splits the vacuum equally between the two SAI
control valves and is located midpoint in front of the
inlet manifold. All vacuum hose lines are protected by
flexible plastic sleeving.
Electrical connection to the SAI vacuum solenoid
valve is via a 2-pin connector. A 12V electrical power
supply to the valve is provided via the Main relay and
Fuse 26 in the engine compartment fusebox. The
ground connection is via the ECM which controls the
SAI vacuum solenoid valve operation. Note that the
harness connector to the SAI solenoid valve is
grey, and must not be confused with the harness
connector to the EVAP system purge valve which
is black.
The ECM switches on the SAI vacuum solenoid valve
at the same time as initiating SAI pump operation.
When the SAI vacuum solenoid valve is open, a
steady vacuum supply is allowed through to open the
two vacuum operated SAI control valves. When the
ECM breaks the earth path to the SAI vacuum
solenoid valve, the valve closes and immediately
shuts off the vacuum supply to the two SAI control
valves at the same time as SAI pump operation is
terminated.
