Toyota 77740-17010 CANISTER Assembly, Charcoal

The Fuel Evaporative Emission Control (EVAP) System functions to store fuel vapors from the fuel tank in a charcoal canister until they can be routed to the intake manifold where they mix within coming air before being burned in the cylinder combustion chambers. A common symptom of a faulty evaporative emissions system is a strong fuel odor in the engine compartment. If a fuel odor is detected, inspect the charcoal canister, located on the lower left side of the engine compartment forward firewall and the EVAP system hoses. A simple check of system operation involves removing the canister and inspecting it for cracks or damage. Check for a clogged filter or stuck check valve by using low pressure compressed air and blowing into the tank pipe to see if air flows without resistance from the other pipes. If it does, replace the canister. Blow into the purge pipe and check that the air does not flow from the other pipes. If this condition is noted, replace the canister. The charcoal canister filter can be cleaned by blowing out the tank pipe with no more than 43 psi (294 kPa) of compressed air while plugging the other upper canister pipe with a finger. The evaporative emissions control system is explained in more detail elsewhere.