Freeze Frame Data Description
Freeze Frame Data allows access to emission-related values from specific generic PIDs. These values are stored when an emission-related DTC is stored in Continuous Memory. This provides a snapshot of the conditions that were present when the DTC was stored. Once one set of freeze frame data is stored, this data will remain in memory even if another emission-related DTC is stored, with the exception of Misfire or Fuel System DTCs. Once freeze frame data for Misfire or Fuel System DTC is stored, it will overwrite any previous data, and freeze frame will not be further overwritten. When a DTC associated with the freeze frame is erased or the DTCs are cleared, new freeze frame data can be stored again. In the event of multiple emission-related DTCs in memory, always note the DTC for the freeze frame data.
FREEZE FRAME DATA TABLE
Some unique parameters (PIDs) are stored in the Keep Alive Memory of the PCM to help in diagnosing the root cause of misfires. These PIDs are collectively called misfire freeze-frame (MFF) data. These parameters are separate from the generic freeze-frame data that is stored for every MIL code. They are used for misfire diagnosis only. The MFF data is more useful for misfire diagnosis than the normal diagnosis only. It is captured at the time of the highest misfire rate and not when the DTC is stored at the end of a 1000 or 200 revolution block. (Generic freeze-frame data for misfire can be stored minutes after the misfire actually occurred.) Note: MFF PIDs are supported on all vehicles but may not be available on all scan tools because enhanced PID access may vary by scan tool manufacturer.
