Fuel Level Sensor: Description and Operation

Fuel Level Sensor
The fuel level sensor is an important input to the PCM for the enhanced EVAP system diagnostic. The PCM needs fuel level information to know the volume of fuel in the tank. The fuel level affects the rate of change of air pressure in the EVAP system.
Several of the enhanced EVAP system diagnostic sub-tests are dependent upon correct fuel level information. The diagnostic will not run when the tank is less than 15% or more than 85% full.
Be sure to diagnose any Fuel Level Sensor DTCs first, as they can cause other DTCs to set.