High Pressure, Normally Low, Variable Force Solenoid Valves
Transmission Control Solenoid Valves 2, 3 and 7 are high pressure, normally low, variable force solenoid valves. This type of solenoid valve regulates hydraulic fluid pressure based on current flow through the solenoid valve coil windings. Each solenoid valve receives 12 V from a high side driver internal to the TCM. Each solenoid valve 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 solenoid coil windings, the force imparted to the armature overcomes the armature spring pressure resulting in an increase in fluid pressure to the controlled element. The normal operating current range for these solenoid valves is between 0-1.2 A. If the TCM detects an electrical circuit malfunction or excessive current flow, the TCM turn 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.