Possible causes
– 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
– 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
Tech description
If the EVAP canister is OK, and there are no other visual damage to the EVAP system (e.g. loose or broken hoses), replacing the vacuum cut valve bypass valve takes care of the problem.
When is the obd code mean?
Vacuum cut valve bypass valve does not operate properly.
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
P1491 NISSAN OBD Code Description