Turbocharger (TC) control valve

WARNING: This page is about a different car, the 2002 Volvo C70, 2001 Volvo C70, 2000 Volvo C70, 1999 Volvo C70, and 1998 Volvo C70. However, it is still accessible from the selected car via links, so may be relevant.

The boost pressure control (BPC) valve is controlled by boost pressure via the turbocharger (TC) control valve (6). An output on the engine control module (ECM) (7) transmits a pulsed signal to the turbocharger (TC) control valve. By altering the signal duty cycle (the pulsing signal) the pressure to the boost pressure control (BPC) valve can be controlled. When the engine control module (ECM) determines that a higher boost pressure is permissible, the duty cycle of the signal to the turbocharger (TC) control valve is increased and a proportion of the pressure acting on the boost pressure control (BPC) valve pressure servo is allowed through to the turbocharger (TC) inlet. Control pressure is reduced, the boost pressure control (BPC) valve opens later and turbocharger (TC) pressure can increase.