1999 S70 tubo Qs
 

On our 1999 S70 turbo the "check engine" light goes on and off (117K miles). Our local Volvo dealer wants $1400 to change both O2 sensors, replace the turbos boost sensor, the "pedal" position sensor, and the fresh air hose to the turbo. Does this sound right? Can anyone tell me what and where the Turbo Boost Sensor is? Same as the "pedal" position sensor.
Thanks

The boost pressure sensor is mounted in the plastic hose that goes to the throttle body.