Freeze Frame Data
FREEZE FRAME DATAEmission-Related Freeze Frame Data
Freeze frame data allows access to emission-related values from specific generic parameter identifications (PIDs). These values are stored when an emission-related diagnostic trouble code (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 remains in memory even if another emission-related DTC is stored, with the exception of misfire or fuel system DTCs. Once freeze frame data for a misfire or fuel system DTC is stored, it overwrites any previous data and freeze frame data is no longer overwritten. When a DTC associated with the freeze frame data 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.
Some unique PIDs are stored in the keep alive memory (KAM) of the powertrain control module (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 stored for every malfunction indicator lamp (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 not when the DTC is stored at the end of a 1,000 or 200 revolution block (Generic freeze-frame data for misfire can be stored minutes after the misfire actually occurred).
The 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.
Non-Emission Related Freeze Frame Data
Freeze frame data allows access to non-emission related values from specific manufacturer's PIDs. These values are stored when a non-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 remains in memory even if another DTC is stored. When a DTC associated with the freeze frame data is cleared or a KAM reset is carried out, new freeze frame data can be stored again.
