ASSEMBLY-TRANSMISSION SOLENOID/TRS
DESCRIPTION
The transmission solenoid/TRS assembly is internal to
the transmission and mounted on the valve body
assembly. The assembly consists of six solenoids that
control hydraulic pressure to the six friction elements
(transmission clutches), and the torque converter
clutch. The pressure control solenoid is located on the
side of the solenoid/TRS assembly. The solenoid/TRS
assembly also contains five pressure switches that
feed information to the TCM.
OPERATION
SOLENOIDS
Solenoids are used to control the L/R, 2C, 4C, OD, and UD friction elements. The reverse clutch is controlled by
line pressure and the position of the manual valve in the valve body. All the solenoids are contained within the
Solenoid and Pressure Switch Assembly. The solenoid and pressure switch assembly contains one additional sole-
noid, Multi-Select (MS), which serves primarily to provide 2nd and 3rd gear limp-in operation.
The solenoids receive electrical power from the Transmission Control Relay through a single wire. The TCM ener-
gizes or operates the solenoids individually by grounding the return wire of the solenoid as necessary. When a
solenoid is energized, the solenoid valve shifts, and a fluid passage is opened or closed (vented or applied),
depending on its default operating state. The result is an apply or release of a frictional element.
The MS and UD solenoids are normally applied to allow transmission limp-in 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 TCM 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 pressure switch error occurs.
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AUTOMATIC TRANSMISSION 545RFE - SERVICE INFORMATION
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