Grand Prix V6-191 3.1L VIN M SFI (1998)
Fuel Tank Pressure Sensor: Description and Operation
Fuel Tank Pressure Sensor
DESCRIPTION
The fuel tank pressure sensor is a three wire strain gauge sensor much like that of the common GM MAP sensor. However, this sensor has very
different electrical characteristics due to its pressure differential design. The sensor measures the difference between the air pressure (or vacuum) in
the fuel tank and the outside air pressure. The sensor mounts at the top of the fuel tank. A three wire electrical harness connects it to the Powertrain
Control Module (PCM).
OPERATION
The PCM supplies a five volt reference voltage and ground to the sensor. The sensor will return a voltage between 0.1 and 4.9 volts. When the air
pressure in the fuel tank is equal to the outside air pressure, such as when the fuel fill cap is removed, the output voltage of the sensor will be 1.3 to 1.7
volts. Refer to Description and Operation of each component for further information and diagnosis of the enhance EVAP system.
