Theory Of Operation

The crankcase of the Engine is exposed to small quantities of combustion gases and oil mist leaking during combustion process through the piston ring gap, called blow-by gases. These gases may be an important source of regulated emissions. Therefore a ventilation system is utilized to recycle the blow-by gases from the crankcase into the air duct in a controlled manner.

The Crankcase Pressure Sensor is used to monitor the pressure inside the crankcase. The Powertrain Control Module (PCM) supplies the Crankcase Pressure Sensor a 5-Volt reference voltage. When the crankcase pressure is low, the sensor signal voltage is low. When the crankcase pressure is high, the sensor signal voltage is near the 5-Volt reference voltage. The PCM monitors the Crankcase Pressure Sensor Signal circuit voltage to calculate the pressure of the air within the crankcase.