Catera V6-3.0L VIN R (1997)
Fuel Tank Pressure Sensor: Description and Operation
Description
The Fuel Tank Pressure sensor mounts to the sending unit at the top of the fuel tank. The Fuel Tank Pressure sensor measures the pressure changes
within the EVAP system. The Fuel Tank Pressure sensor has a 5.0 volt reference, a ground and a signal circuit.
Operation
The Fuel Tank Pressure sensor contains a diaphragm which changes the resistance based on the pressure. When the EVAP system pressure is low (during
purge), the sensor output voltage is low. When the system pressure is high, the sensor output voltage is high. The signal from this sensor provides
feedback to the ECM on the EVAP system operation. The ECM's programming contains an expected system behavior during the various EVAP system
operating conditions. The ECM monitors the EVAP system pressure.
Circuit Malfunctions
If the Fuel Tank Pressure sensor signal is outside of the normal operating range of the sensor, the DTC P0450 - Fuel Tank Pressure Sensor Circuit will
set.
If the Fuel Tank Pressure sensor signal differs from an expected result during an EVAP system test (caused by either a sensor problem or an actual
EVAP system problem), the following Diagnostic Trouble Codes (DTCs) can set:
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DTC P0440 - EVAP System
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DTC P0455 - EVAP System Large Leak Detected