Lock-Up-Solenoid, SLU
The lock-up solenoid, SLU is located in the transmission control system, which is fitted on the front edge of the gearbox. The lock-up solenoid, SLU consists of an electrical coil which controls a hydraulic valve. The solenoid is controlled with a pulsed (PWM) voltage and is grounded via the Transmission Control Module (TCM). The solenoid controls torque converter lock-up engagement. The engagement takes place by means of the solenoid being pulsed in, which enables a gentle engagement of the lock-up function. The solenoid permits the torque converter to work in one of three positions: "Open", "Controlled slipping" and "Locked". The hydraulic function of the solenoid is linear.
The solenoid can be diagnosed.