Freeze Frame Data: Description
Freeze frame data records the engine conditions (fuel system, calculated load, engine coolant temperature, fuel trim, engine speed, vehicle speed, etc.) when a malfunction is detected. When troubleshooting, it can help determine if the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was LEAN or RICH, and other data, from the time the malfunction occurred.
HINT:
If it is impossible to replicate the problem even though a DTC is detected, confirm the freeze frame data.
The ECM records engine conditions in the form of freeze frame data every 0.5 seconds. Using the hand-held tester, five separate sets of freeze frame data, including the data values at the time when the DTC was set, can be checked.
- 3 data sets before the DTC was set
- 1 data set when the DTC was set
- 1 data set after the DTC was set
These data sets can be used to simulate the condition of the vehicle around the time of the occurrence of the malfunction. The data may assist in identifying of the cause of the malfunction, and in judging whether it was temporary or not.