A 2001 Frontier (D22) or Xterra (WD22) may exhibit one or both of the following symptoms:

• MIL “On” with DTC P1491 (Vacuum Cut Valve Bypass Valve – VC CUT/V BYPASS/V) stored in the ECM; and/or
• Difficulty refueling the vehicle.

Service Procedure
Warning: Before performing any of the Service Procedures below, be certain there are no ignition sources (i.e., open flames, sparks, etc.) in or around the vehicle/work area. Make sure the appropriate rated fire extinguisher is available for immediate use.

MIL “On” With DTC P1491 Stored:

1. Connect CONSULT-II.
2. Turn the ignition key to “on” but do not start the engine.
3. Select “ENGINE,” “DATA MONITOR,” “EVAP SYSTEM PRESSURE SENSOR.”
4. The pressure sensor value should read between 3.32 and 3....