P1440 INFINITI, NISSAN: EVAPORATIVE EMISSION CONTROL SYSTEM SMALL LEAK
Description of DTC code P1440
The Evaporative Emissions Control System (EVAP) prevents fuel vapors from passing into the atmosphere and causing damage to the atmosphere. Instead, the vapor contained in the fuel system is sent back to the engine through the intake manifold.
EVAP diagnostics detect a leak in the purge line. To do this, it uses vapor pressure in the fuel tank. The EVAP tank vent control valve is closed to block the purge line. Consequently, the bypass valve opens to clear the line between the tank and the solenoid, controlling the purge volume of the canister. Then, the pressure sensor of the EVAP control system monitors the pressure inside the fuel tank. In case the pressure increases, the ECM (Engine Control Module) checks for leaks in the line between the vacuum shut-off valve and the purge control solenoid.
The P1440 OBDII fault code P1440 is set when the EVAP Control System is leaking, causing the EVAP Control System to malfunction.