Boost Pressure Monitoring

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 Engine Control Module (ECM) constantly monitors boost pressure using the mass air flow (MAF) sensor and the intake air pressure sensor. If boost pressure exceeds permitted levels the Engine Control Module (ECM) shuts the turbocharger (TC) control valve so that the engine torque can only be controlled through limiting the throttle opening. A diagnostic trouble code (DTC) is stored at the same time.

If the calculations display too low boost pressure a diagnostic trouble code is stored.

If a fault occurs in a component that affects boost pressure calculation, the Engine Control Module (ECM) will always limit throttle opening.

If there is a fault in any of the sensors the boost pressure control goes over in an open loop. This means that it is controlled by fixed duty cycle which is a direct function of accelerator pedal (AP) position and engine speed (RPM).