Shift Pressure Control Solenoid Valve (SLS) (340): Notes
WARNING: This page is about a different car, the 2009 Pontiac Torrent and 2009 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.
The shift pressure control solenoid valve (normally high, 3-port linear pressure control solenoid) is a precision electronic pressure regulator that controls transmission clutch apply pressure based on current flow through its coil windings. As current flow is increased, the magnetic field produced by the coil moves the solenoid's plunger further away from the exhaust port. Opening the exhaust port decreases the output fluid pressure regulated by the shift pressure control solenoid valve, which ultimately decreases clutch apply pressure. The TCM controls the shift pressure control solenoid valve based on various inputs including throttle position, transmission fluid temperature and gear state.