DTC P0442, DTC P0455 Or DTC P1442: EVAP Control System: Description

WARNING: This page is about a different car, the 2003 Infiniti Q45. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: If DTC P0442, P0455 or P1442 is displayed with P1448, first perform trouble diagnosis for DTC P1448. See DTC P1448: EVAP CANISTER VENT CONTROL VALVE (OPEN) .

For DTC P0442, this diagnosis detects leaks in the EVAP purge line using engine intake manifold vacuum. If pressure does not increase, the ECM will check for leaks in the line between the fuel tank and EVAP canister purge volume control solenoid valve, under the following conditions: The vacuum cut valve by-pass valve is opened to clear the line between the fuel tank and the EVAP canister purge volume control solenoid valve. The EVAP canister vent control valve will then be closed to shut the EVAP purge line off. The EVAP canister purge volume control solenoid valve is opened to depressurize the EVAP purge line using intake manifold vacuum. After this occurs, the EVAP canister purge volume control solenoid valve will be closed.

For DTC P0455, this diagnosis detects a very large leak (fuel filler cap fell off etc.) in EVAP system between the fuel tank and EVAP canister purge volume control solenoid valve.

For DTC 1442, this diagnosis detects leaks in the EVAP purge line using vapor pressure in the fuel tank. The EVAP canister vent control valve is closed to shut the EVAP purge line. The vacuum cut valve by-pass valve will then be opened to clear the line between the fuel tank and the EVAP canister purge volume control solenoid valve. The EVAP control system pressure sensor can now monitor the pressure inside the fuel tank. If pressure increases, the ECM will check for leaks in the line between the vacuum cut valve and EVAP canister purge volume control solenoid valve.