Circuit Description

The Engine Control Module (ECM) uses the fuel level input from the Fuel Level Sensor to calculate expected vapor pressures within the fuel system. Vapor pressures vary as the fuel level changes. Vapor pressure is critical in determining if the Evaporative (EVAP) emission system is operating properly. Fuel level is also used to determine if the fuel level is too high or too low to be able to accurately detect EVAP emission system faults.