Positive Crankcase Ventilation (PCV) System Monitor

WARNING: This page is about a different car, the 2007 Mercury Mariner and 2007 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

The PCV monitor consists of a modified PCV system design. The PCV valve is installed into the rocker cover using a quarter-turn camlock design to prevent accidental disconnection. High retention force molded plastic lines are used from the PCV valve to the intake manifold. The diameter of the lines and the intake manifold entry fitting are increased so that inadvertent disconnection of the lines after a vehicle is repaired either causes an immediate engine stall or does not allow the engine to be restarted. In the event that the vehicle does not stall if the line between the intake manifold and PCV valve is inadvertently disconnected, the vehicle has a large vacuum leak that causes the vehicle to run lean at idle. This illuminates the malfunction indicator lamp (MIL) after 2 consecutive driving cycles and stores one or more of the following diagnostic trouble codes (DTC)s: lack of heated oxygen sensor (HO2S) switches, bank 1 (P2195), fuel system lean, bank 1 (P0171).

For additional PCV information, refer to POSITIVE CRANKCASE VENTILATION (PCV) SYSTEM .