Diagnosis Conditions

Engine idling
Vehicle speed = 0 km/h
Oxygen sensing system active
Time elapsed after engine start-up > 675 sec
No secondary air diagnosis
Air mass < 30 kg/h
Engine temperature > 60°
Altitude correction factor > 0.75
No faults: Throttle position sensor, idle air control, vehicle speed, EVAP canister purge valve output stage, mass air flow sensor, load signal, voltage supply and engine temperature.

NOTE: Fuel tank ventilation diagnosis is initiated with the Porsche System Tester 2 in the "Short Test" menu. This reduces the time elapsed after engine start-up to 30 seconds.

Fig 1: DTC P0440 Fault Conditions

Courtesy of PORSCHE OF NORTH AMERICA, INC.

NOTE: The EVAP canister purge valve is very sensitive to contamination. If the lines to the EVAP canister have to be detached, the outside of the canister must be cleaned beforehand .