Solenoid/Pressure Switch Assy - Chrysler 300M Service Manual

LH
SHIFT MECHANISM (Continued)
Fig. 378 Shifter Assembly Removal/Installation
1 - NUT
2 - SHIFTER ASSEMBLY
(7) Slip interlock cable conduit end fitting into
bracket and snap into place (Fig. 377).
(8) If equipped with Autostick, connect the Auto-
stick connector.
(9) Adjust gear shift and interlock cables.
NOTE: Gearshift and interlock cables MUST be
adjusted. Refer to the Adjustments section in this
Group for the correct procedures.
SOLENOID/PRESSURE
SWITCH ASSY
DESCRIPTION
The Solenoid/Pressure Switch Assembly (Fig. 379)
is inside the transaxle and mounted to the valve
body assembly. The assembly consists of four sole-
noids that control hydraulic pressure to the L/R, 2/4,
OD, and UD friction elements (transaxle clutches),
and the torque converter clutch. The reverse clutch is
controlled by line pressure from the manual valve in
the valve body. The solenoids are contained within
the Solenoid/Pressure Switch Assembly, and can only
be serviced by replacing the assembly.
The solenoid assembly also contains pressure
switches that monitor and send hydraulic circuit
information to the PCM. Likewise, the pressure
switches can only be service by replacing the assem-
bly.
Fig. 379 Valve Body Assembly
1 - SOLENOID/PRESSURE SWITCH ASSEMBLY
2 - TRS
3 - TRANSFER PLATE
4 - SEPARATOR PLATE
5 - VALVE BODY
OPERATION
SOLENOIDS
The solenoids receive electrical power from the
Transmission Control Relay through a single wire.
The PCM energizes or operates the solenoids individ-
ually by grounding the return wire of the solenoid
needed. When a solenoid is energized, the solenoid
valve shifts, and a fluid passage is opened or closed
(vented or applied), depending on its default operat-
ing state. The result is an apply or release of a fric-
tional element.
The 2/4 and UD solenoids are normally applied,
which allows fluid to pass through in their relaxed or
"off" state. By design, this allows transaxle limp-in
(P,R,N,2) in the event of an electrical failure.
The continuity of the solenoids and circuits are
periodically tested. Each solenoid is turned on or off
depending on its current state. An inductive spike
should be detected by the pcm during this test. If no
spike is detected, the circuit is tested again to verify
the failure. In addition to the periodic testing, the
solenoid circuits are tested if a speed ratio or pres-
sure switch error occurs.
PRESSURE SWITCHES
The PCM relies on three pressure switches to mon-
itor fluid pressure in the L/R, 2/4, and OD hydraulic
circuits. The primary purpose of these switches is to
TRANSAXLE 21 - 141