Dodge RAM TRUCK 1500 1995 Service Manual page 1705

iR EiiSSiOi CONTROL SYSTEMS 21 - 7
POWERTRAih CONTROL
MODULE (PCM) J94U-11
Fig. 2 PCM and Data Link Connector
Fig. 3 Solenoid Location—3.9U5.2U5.9L Engines-
Typical
vent vacuum from reaching the EVAP canister valve.
When the engine reaches an operating temperature
of approximately 27°C (80°F) and a time delay inter­
val of about 100 seconds has occurred, the PCM re­
moves the ground to solenoid. The de-energized
solenoid allows vacuum to flow to the EVAP canister
and purge fuel vapors through the intake manifold.
The EVAP canister purge solenoid will also be en­
ergized during certain idle conditions in order to up­
date the fuel delivery calibration.
If a failure has occurred in the purge solenoid cir­
cuit, a diagnostic trouble code (DTC) will be stored in
the powertrain control module (PCM) memory. Refer
to On-Board Diagnostics in Group 14, Fuel Systems
for DTC information.
Refer to the Component Removal/Installation sec­
tion of this group for replacement procedures.
PRESSURE RELIEF/ROLLOVER VALVE
These vehicles are equipped with a combination
pressure relief and rollover valve. This dual function
J9425-16
Fig. 4 Solenoid Location—S.OL V-10 Engine—Typical
valve will relieve fuel tank pressure and also prevent
fuel flow through the fuel tank vent hoses in the
event of an accidental vehicle rollover.
The valve incorporates a pressure relief mechanism
that releases fuel tank pressure when the pressure
increases above the calibrated sealing value. Refer to
the Fuel Tank section of Group 14, Fuel Systems for
removal and installation procedures.
FUEL TANK FILLER TUBE CAP
The fuel tank is sealed with a pressure-vacuum re­
lief fuel tank filler tube cap (fuel tank cap-—figure 5).
The relief valves in the cap are a safety feature. They
operate only to prevent excessive pressure or vacuum
in tank caused by a malfunction in system or damage
to vent lines.
PLASTIC
GASKET
RN348
Fig. 5 Fuel Tank Filler Tube Cap—Typical