High Pressure Normally High, Variable Force Solenoid Valve
Transmission Control Solenoid Valve 4 is a high pressure, normally high, variable force solenoid valve. This type of solenoid valve regulates hydraulic fluid pressure based on current flow through the solenoid valve coil windings. Each solenoid receives 12 V from a high side driver internal to the TCM. This solenoid has a control circuit to an individual low side driver internal to the TCM, which turns ON and OFF to control the amount of current. As an increasing current is applied to the coil windings, the force imparted to the armature overcomes the high fluid pressure acting on the solenoid valve armature resulting in a decrease in fluid pressure to the controlled element. The normal operating current range for this solenoid is between 0-1.2 A. If the TCM detects an electrical circuit malfunction or excessive current flow, the TCM turns off the high side driver to that solenoid and sets a DTC. The high side driver will reset when the circuit fault is corrected and the ignition switch is cycled.