Range Rover P38
LAND ROVER V8
29
DESCRIPTION AND OPERATION
Certain failure modes may cause the 5V supply
voltage which is shared with the throttle position
sensor to be reduced to less than 1V.
Fault codes:
•
P0451 - Fuel tank pressure sensor poor
performance fault
•
P0452 - Fuel tank pressure sensor low range
fault
•
P0453 - Fuel tank pressure sensor high range
fault
See EMISSION CONTROL, Description and
operation.
EVAP Canister Purge Valve
The purge valve is controlled by the GEMS ECM and
allows hydrocarbons stored in the EVAP canister to
be purged to the engine inlet manifold for burning.
Electrical circuit integrity and system flow checks are
performed.
If a purge valve breaks or becomes stuck, the purge
system will cease to function, and there is no default
operation measures. GEMS will store the fault if the
correct monitoring conditions have been achieved (45
seconds after 15 minutes running). If a valve is stuck
open, the engine may misfire and the fuelling
adaptions will change.
The following failure modes are possible:
•
Sticking valve
•
Valve blocked
•
Connector or harness wiring fault (open or short
circuit)
•
Valve stuck open
Fault codes:
•
P0441 - Purge valve flow fault
•
P0443 - Purge valve open or short circuit
See EMISSION CONTROL, Description and
operation.
EVAP Canister Vent Solenoid (CVS) Valve
The CVS unit is located at the left hand side of the
engine bay. The vent seal valve is normally open.
When the GEMS ECM is required to run a fuel system
test, the vent valve is closed to seal the system. The
ECM is then able to measure the pressure in the fuel
system using the fuel tank pressure sensor. Electrical
integrity checks are performed on the CVS valve and
a valve blockage can be determined from a
depressurising fuel tank.
The following failure modes are possible:
•
Connector or harness wiring fault (open or short
circuit)
•
Valve stuck open or shut
•
Valve blocked
See EMISSION CONTROL, Description and
operation.
