Freeze Frame Data

ECM stores engine and driving conditions at moment of detection of a malfunction in its memory. This data is called "Freeze Frame Data".

Therefore it is possible to know engine and driving conditions (e.g. whether engine is warm or not, where vehicle was running or stopped, where air/fuel mixture was lean or rich) when a malfunction was detected by checking freeze frame data. Also, ECM has a function to store each freeze frame data for three different malfunctions in order as malfunction is detected. Utilizing this function, it is possible to know order of malfunction that have been detected. Its use is helpful when rechecking or diagnosing a trouble.