SYSTEMS AND METHODS FOR FUEL VAPOR STORAGE CANISTER WORKING CAPACITY DIAGNOSTICS

Methods and systems are provided for assessing a working capacity of a fuel vapor storage canister positioned in an evaporative emissions system configured to capture and store fuel vapors from a fuel system. In one example, a method comprises, in response to fuel vapor being adsorbed by, or desorbed from, the fuel vapor canister, sealing the evaporative emissions system and indicating degradation of the fuel vapor canister in response to a monitored pressure change in the evaporative emissions system less than a threshold pressure change. In this way, working capacity of the fuel vapor storage canister is inferred, which may allow for a reduction in undesired evaporative emissions to atmosphere.