Misfire Detection Monitor

Misfire is defined as lack of proper combustion in cylinder due to absence of spark, poor fuel metering, or poor compression. Any combustion that does not occur within the cylinder(s) at the proper time is also a misfire. Misfire detection monitor detects fuel, ignition or mechanically induced misfires. The intent is to protect catalyst from permanent damage and to alert customer of an emission failure or an Inspection/Maintenance (I/M) failure by illuminating Malfunction Indicator Light (MIL). When a misfire is detected, special software called "Freeze Frame" data is enabled. Freeze Frame data captures operational state of vehicle when a fault is detected from misfire detection monitor strategy. For additional Freeze frame data information, see FREEZE FRAME DATA MODE  under ADDITIONAL SYSTEM FUNCTIONS.