Lock-Up Solenoid, SLU
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.
The lock-up solenoid (SLU) is located on the transmission control system, which is fitted on the front edge of the transmission. The lock-up 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 control module regulates the lock-up engagement of the torque converter. During lock-up, the solenoid is pulsed in, which makes lock-up engagement gentle. The solenoid allows the torque converter to work in one of three modes: "open", "controlled slippage" and "locked". The solenoid has a linear hydraulic function.
The solenoid can be diagnosed.