Lock-up solenoid, SL
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Volvo S80, 2005 Volvo S80, 2004 Volvo S80, 2003 Volvo S80, and 2002 Volvo S80. However, it is still accessible from the selected car via links, so may be relevant.
Lock-up solenoid SL is positioned in the valve housing, which is mounted behind the side cover on the transmission. The lock-up solenoid consists of an electrical coil which controls a hydraulic valve. The solenoid is controlled by pulse width modulation (PWM) voltage and is grounded at the ground terminal. The solenoid controls lock-up engagement of the torque converter. Engagement occurs through solenoid pulsing which provides a smooth lock-up engagement function. Power transmission then changes to mechanical power transmission through the torque converter. The hydraulic function of the solenoid is linear.
There is a diagnostic for the electrical function of the solenoid, but not for the hydraulic function.