Generator Monitor
WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2002 Mercury Sable, 2002 Mercury Mountaineer, 2002 Mercury Grand Marquis, 2002 Mercury Cougar, and 2002 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
The regulator uses a Generator Monitor (GEN MON) signal to provide feedback to Powertrain Control Module (PCM) with charging system information. GEN MON signal lets PCM know when the charging system receives a transient electrical load which would normally affect idle stability. Because PCM can anticipate additional loads, PCM can choose to reduce regulator set point or increase engine idle speed, both of which are calibratable features. Charge indicator will be illuminated if PCM fails to see a signal on generator monitor line for a time period greater than 500 milliseconds. This telltale command will also be used to indicate over-voltage conditions detected by PCM controlled generator.