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How to test an EVAP charcoal canister

Charcoal Canister Operation

The main job of the charcoal canister is to absorb and store fuel vapor. It is filled with activated charcoal that absorbs fuel vapor or hydrocarbons from the gas tank during normal venting. It then stores that vapor it until the system is ready to purge them into the engine to be burned.

Charcoal Canister Simple Testing

  1. Visual Inspection - Check the charcoal canister for any physical damage, such as cracks, broken ports, etc.
illustration of charcoal canister
  1. Check for contamination - Remove canister and check for liquid fuel inside the canister, if liquid fuel is found the canister needs replacement.
illustration of fluid filled charcoal canister
  1. Check air flow - Check that canister is not clogged and air can flow through canister easily
illustration of drawing of charcoal canister with air flowing thru
Tip : To avoid repeat failure, if contamination is found, check system for root cause, such as topping off fuel or driving in off-road conditions