On Board Diagnosis Logic

WARNING: This page is about a different car, the 2005 Infiniti QX56. However, it is still accessible from the selected car via links, so may be relevant.

Under normal conditions (non-closed throttle), sensor output voltage indicates if pressure drop and purge flow are adequate. If not, a malfunction is determined.

Fig 1: DTC P0441 EVAP Control System - On Board Diagnosis Logic

Courtesy of NISSAN MOTOR CO., U.S.A.