Solenoid and Pressure Switch Assembly

DESCRIPTION
The solenoid and pressure switch assembly is external to the transaxle and mounted to the valve body assembly. The assembly consists of four solenoids that control hydraulic pressure to four of the five friction elements (transaxle clutches), and the torque converter clutch. The solenoid assembly also contains pressure switches that feed information to the Transmission Control Module (TCM).

OPERATION
The solenoids within the assembly are supplied voltage by the Transmission Control Relay. The solenoids are energized when the TCM grounds the return wire for the solenoid that is needed. The pressure switches simply tell the TCM whether or not pressure exists within a clutch circuit. Refer to "Pressure Switches" for more information regarding pressure switches.

BATTERY FEED (TCM)
A fused, direct battery feed to the TCM is used for continuous power. The battery feed is spliced and also fed to the contact side of the Transmission Control Relay. This battery voltage is necessary to retain adaptive learn values in the TCM's RAM (Random Access Memory). When the battery (B+) is disconnected, this memory is lost. When the battery (B+) is restored, this memory loss is detected by the TCM and a Diagnostic Trouble Code (DTC) is set.