Circuit Description

PCM uses fuel level input from fuel level sensor in order to calculate expected vapor pressures within fuel system. Vapor pressures vary as fuel level changes. Vapor pressure is critical to determining if EVAP control system is operating properly. Fuel level information is used in determining whether to run an EVAP control system diagnostic. Fuel level that is too high or too low may prevent EVAP control system diagnostics from accurately detecting a fault.

DTC will set when change in fuel level reading does not exceed a specified value during a set period of engine operation, and condition is present once per drive cycle.