Technical Description
- To judge if there is a leak or clog in the fuel system, the ECM (M/T) or PCM (A/T) measures the change of pressure in the fuel tank.
- The ECM (M/T) or PCM (A/T) turns on the evaporative emission ventilation solenoid to shut off the evaporative emission canister outlet port.
- Then the evaporative emission purge solenoid is driven to set the fuel system into a negative pressure.
- When the fuel system develops a vacuum of 0.92 psi (2 kPa), the evaporative emission purge solenoid is turned "off" and the fuel system vacuum is maintained at 0.29 psi (2 kPa).
- The ECM (M/T) or PCM (A/T) determines if there is leak or clog in the fuel system by measuring the change of vacuum inside the fuel tank.
- The test is stopped when fuel vapor pressure is judged as too high.