Freeze Frame Data Mode: Description
FREEZE FRAME DATA MODE allows access to emission-related values from specific generic Parameter Identifications (PIDs). These PID values are stored when an emission-related DTC is stored in continuous memory and provide a snapshot of the conditions that were present when DTC was stored. See FREEZE FRAME DATA table.
| Acronym | Description | Measurement Units |
|---|---|---|
| ECT | Engine Coolant | Degrees |
| FUELSYS1 | Open/Closed Loop1 | OL/CL/OL, Drive/OL, Fault CL, Fault |
| FUELSYS2 | Open/Closed Loop2 | OL/CL/OL, Drive/OL, Fault CL, Fault |
| LONGFT1 | Long Term Fuel Bank1 | Percent |
| LONGFT2 | Long Term Fuel Bank2 | Percent |
| LOAD | Calculated Load Value | Percent |
| RPM | Engine RPM | Rev/Min |
| SHRTFT1 | Short Term Fuel Bank1 | Percent |
| SHRTFT2 | Short Term Fuel Bank2 | Percent |
| VSS | Vehicle Speed | MPH/KMH |
Freeze frame data will remain in memory even if another emission-related DTC is stored, with exception to misfire or fuel system DTCs. When freeze frame data for a misfire or fuel system DTC is stored, it will overwrite any previous data and freeze frame data will not be overwritten. When freeze frame DTCs are erased or a PCM memory reset is performed, new freeze frame data will be stored. If multiple emission-related DTCs are stored in memory, always note freeze frame data DTC. Some unique PIDs are stored in PCM keep alive RAM to help in diagnosing root causes to misfires. See MISFIRE FREEZE-FRAME PIDS table.
These unique PIDs are collectively called Misfire Freeze Frame (MFF) data. These PIDs are separate from generic freeze frame data that is stored for MIL codes and are used for misfire diagnosis only. MFF data is more useful for misfire diagnosis than normal diagnosis alone. MFF is captured at time of highest misfire rate, not when DTCs are normally stored at the end of a 1000 or 200 revolution block. Generic freeze frame data for a misfire can be stored minutes after a misfire actually occurs.
| PID | Description | PID No. | Units |
|---|---|---|---|
| MFF RPM | Engine RPM At Time Of Misfire | 16D3 | RPM |
| MFF LOAD | Engine Load At Time Of Misfire | 16D4 | PERCENT |
| MFF VS | Vehicle Speed At Time Of Misfire | 16D5 | MPH/KPH |
| MFF IAT | Intake Air Temperature At Time Of Misfire | 16D6 | DEGREES |
| MFF SOAK | Engine-Off Soak Time At Time Of Misfire | 16D7 | MINUTES |
| MFF RNTM | Engine Running Time At Time Of Misfire | 16D8 | SECONDS |
| MFF EGR | EGR DPFE Sensor At Time Of Misfire | 16D9 | VOLTAGE |
| MFF TP | Throttle Position At Time Of Misfire | 16DA | VOLTAGE |
| MFF T CNT | No. Of Driving Cycles At Time Of Misfire (At Least One 1000 Revolution Block) | 16DC | TRIPS |
| MFF PNP | 1= In Drive During Time Of Misfire | 16DD b1 | MODE |
| MP LRN | 1= Misfire Wheel Profile Learned In Keep Alive RAM | 16DD b0 | NONE |