Which mode is appropriate for checking freeze frame data to see engine conditions when a diagnostic trouble code was set?

The appropriate mode for checking freeze frame data to see engine conditions when a diagnostic trouble code (DTC) is set is Mode 2.

Freeze frame data is a snapshot of the engine's operating conditions at the time the DTC was triggered. This data can include information such as engine RPM, coolant temperature, vehicle speed, and throttle position, which can be critical for diagnosing issues. Mode 2 specifically provides this freeze frame information, allowing the technician to analyze the conditions present when the fault occurred.

In contrast, other modes focus on different types of data. For example, Mode 1 typically gives real-time data but does not include the historical snapshot that freeze frame data provides. Modes 3 and 4 may relate to different sets of diagnostic information but are not specifically utilized for accessing freeze frame data. Therefore, utilizing Mode 2 is essential for effectively diagnosing the problem by examining the specific engine conditions that were present at the time the DTC was recorded.