Chrysler Pacifica. Manual — part 906

PCV VALVE

DESCRIPTION

The PCV valve contains a spring loaded plunger.

The plunger meters the amount of crankcase vapors
routed into the combustion chamber based on intake
manifold vacuum.

DIAGNOSIS AND TESTING - PCV SYSTEM

WARNING:

APPLY

PARKING

BRAKE

AND/OR

BLOCK WHEELS BEFORE PERFORMING ANY TEST
OR ADJUSTMENT WITH THE ENGINE OPERATING.

(1) With engine idling, remove the hose from the

PCV valve. If the valve is not plugged, a hissing
noise will be heard as air passes through the valve. A
strong vacuum should also be felt when a finger is
placed over the valve inlet.

(2) Install

hose

PCV

valve.

Remove

the

make-up air hose from the air plenum at the rear of
the engine. Hold a piece of stiff paper (parts tag)
loosely over the end of the make-up air hose.

(3) After allowing approximately one minute for

crankcase pressure to reduce, the paper should draw
up against the hose with noticeable force. If the
engine does not draw the paper against the grommet
after installing a new valve, replace the PCV valve
hose.

(4) Turn the engine off. Remove the PCV valve

from intake manifold. The valve should rattle when
shaken.

(5) Replace the PCV valve and retest the system if

it does not operate as described in the preceding
tests. Do not attempt to clean the old PCV valve.

REMOVAL

(1) Remove hose from PCV valve. The valve is on

the rear valve cover (Fig. 13).

(2) Unscrew the PCV valve.
(3) Remove PCV valve.

INSTALLATION

(1) Install PCV valve and tighten (Fig. 14).
(2) Install PCV hose.

VAPOR CANISTER

OPERATION

All vehicles use a maintenance free, evaporative

(EVAP) canister. Fuel tank vapors vent into the can-
ister. The canister temporarily holds the fuel vapors
until intake manifold vacuum draws them into the
combustion chamber. The Powertrain Control Module
(PCM) purges the canister through the proportional

purge solenoid. The PCM purges the canister at pre-
determined intervals and engine conditions.

Purge Free Cells

Purge-free memory cells are used to identify the

fuel vapor content of the evaporative canister. Since
the evaporative canister is not purged 100% of the
time, the PCM stores information about the evapora-
tive canister’s vapor content in a memory cell.

The purge-free cells are constructed similar to cer-

tain purge-normal cells. The purge-free cells can be

Fig. 13 PCV VALVE AND HOSE

1 - PCV Hose
2 - PCV valve

Fig. 14 PCV VALVE AND HOSE

1 - PCV Hose
2 - PCV valve

EVAPORATIVE EMISSIONS

25 - 15

monitored by the DRB III

t Scan Tool. The only dif-

ference between the purge-free cells and normal
adaptive cells is that in purge-free, the purge is com-
pletely turned off. This gives the PCM the ability to
compare purge and purge-free operation.

REMOVAL

(1) Raise vehicle and support.
(2) Remove the hoses from the EVAP canister.
(3) Remove the 2 mounting nuts (Fig. 15).
(4) Remove the inboard screw from the mounting

bracket.

(5) Loosen the 2 other screws.
(6) Remove the canister.

INSTALLATION

(1) Install canister into bracket (Fig. 16).
(2) Tighten 2 mounting nuts.
(3) Install inboard screw and tighten all 3 bracket

mounting screws.

(4) Connect the EVAP canister hoses.
(5) Lower vehicle.

Fig. 15 EVAP CANISTER MOUNTING NUTS

Fig. 16 EVAP CANISTER MOUNTING NUTS

25 - 16

EVAPORATIVE EMISSIONS

VAPOR CANISTER (Continued)