OBD II EVAP - Fuel Tank Vacuum Sensing (Enhanced EVAP)

On-board Refuelling Vapor Recovery System Component Views:

The basic Evaporative Emission ([1][2]EVAP) Control system used on all vehicles is the charcoal canister storage method. This method transfers fuel vapor from the fuel tank to an activated carbon (charcoal) storage device (canister) to hold the vapors when the vehicle is not operating. When the engine is running, the fuel vapor is purged from the carbon element by intake air flow and consumed in the normal combustion process.

The evaporative system includes the following components:
^ Fuel tank
^ Evaporative emission canister vent solenoid
^ Fuel tank pressure sensor Fuel pipes and hoses
^ Vapor lines
^ Fuel cap
^ Evaporative emission canister
^ Purge lines
^ Purge valve solenoid

Results of Incorrect Operation
Poor idle, stalling and poor driveability can be caused by:
^ Malfunctioning purge solenoid.
^ Damaged canister.
^ Hoses/lines split, cracked and/or not connected properly.

Visual Check of Evaporative Emission Canister
^ Cracked or damaged, replace canister.
^ Fuel leaking from the canister, replace canister and check lines and line routing.