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Home >> Volvo >> 2002 >> V70 XC >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Alarm System, Control Modules, Engine Management Systems - Design And Function >> Central Electronic Module (CEM) (2005-2007) >> Design >> Twilight sensor
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Twilight sensor

Fig 1: Sun Sensor
GLL108066Courtesy of VOLVO CARS OF NORTH AMERICA.

The twilight sensor consists of a photo diode powered from the central electronic module (CEM). The conductivity of the diode depends on the amount of light to which it is exposed.

The diode is under a diffusing lens which reduces the sensitivity of the photo diode to the angle of the light hitting it. Increased light intensity reduces the voltage over the photo diode.

The control module measures the voltage across the photo diode and converts the voltage to information which is then transmitted to other control modules via the controller area network (CAN).

The twilight sensor is in the same holder as the sun sensor.

There are diagnostics for the twilight sensor.