Mopar 4891757AD Vapor Canister

The EVAP system utilizes a canister filled with activated charcoal to absorb and store fuel vapors. The fuel tank filler cap is equipped with a two-way valve that vents fuel vapors to the atmosphere in the event of a system failure. A check valve regulates the flow of fuel vapor from the tank to the canister, preventing fuel flow when the tank is full or during a rollover accident. The EVAP system is electronically controlled by the PCM, which operates a purge control solenoid to open a diaphragm valve in the canister, allowing fuel vapors to be drawn into the intake manifold. The PCM controls the rate of flow by adjusting the duty cycle of the solenoid. A leak detection monitor system is also in place to detect any leaks in the EVAP system.

The function of the evaporative emissions control system is to draw fuel vapors from the gas tank and fuel system, temporarily store them in a charcoal canister, and route them to the intake manifold during normal engine operation.