sandrk

I have a 2000 nissan sentra with service engine soon code P1491. It comes on at about 140 miles after having it reset and it will go off after about 300 miles seems to be pretty consistent.
any help?

saint0421

from the FSM hope this helps:

DTC P1491 VACUUM CUT VALVE BYPASS VALVE PFP:17372
Description UBS000CJ
COMPONENT DESCRIPTION
The vacuum cut valve and vacuum cut valve bypass valve are
installed in parallel on the EVAP purge line between the fuel tank and
the EVAP canister.
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.

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