Linear Pressure Solenoid, SLT

WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2009 Volvo S60, 2008 Volvo S60, 2007 Volvo S60, 2006 Volvo S60, and 2005 Volvo S60. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Identifying SLT Solenoid In Transmission Control System

Courtesy of VOLVO CARS OF NORTH AMERICA.

The linear pressure solenoid (SLT) is located in the transmission control system, which is fitted on the front edge of the transmission. The linear pressure solenoid, consists of an electrical coil that controls a hydraulic valve. The solenoid is controlled with a pulse width modulated (PWM) voltage and is grounded via the transmission control module (TCM). The solenoid has a linear hydraulic function. The hydraulic valve is controlled by the varying current resulting from the current pulse ratio. With a high pulse ratio, i.e. high current strength (approx. 1 A), the system pressure is low. With a low pulse ratio, i.e. low current strength, the system pressure is high. In the event of an open circuit the system pressure is at a maximum, resulting in hard shifting. The hydraulic valve is then fully open.

The solenoid can be diagnosed.