P1491 NISSAN - Vacuum Cut Valve Bypass Valve
- Vacuum cut valve
- Bypass hoses for clogging
- EVAP control system pressure sensor and circuit
- EVAP canister vent control valve
- Hose between fuel tank and vacuum cut valve clogged
- Hose between vacuum cut valve and EVAP canister clogged
- EVAP purge port of fuel tank for clogging
There is a factory service bulletin for all 1998-2002 Nissan models.
1998-2002 Nissan Factory Service Bulletin OBDII Code P1491
The vacuum cut valve prevents the intake manifold vacuum from being applied to the fuel tank. The vacuum cut valve bypass valve is a solenoid type valve and generally remains closed. It opens only for on board diagnosis.
The vacuum cut valve bypass valve responds to signals from the ECM. When the ECM sends an ON (ground) signal, the valve is opened. The vacuum cut valve is then bypassed to apply intake manifold vacuum to the fuel tank.
P1491 2003 NISSAN ALTIMA SEDAN
P1491 2000 NISSAN SENTRA
P1491 2001 NISSAN SENTRA