What is DTC snapshot information?

What is DTC snapshot information?

DTC snapshot information is a specific data record obtained through the UDS protocol to help diagnose vehicle faults. According to the ISO
14229 standard, DTC snapshot information is like a camera. When a fault occurs, it takes a photo of the entire vehicle and makes a record for subsequent problem analysis.

DTC snapshot information can include multiple aspects of data, such as fault codes, fault conditions, sensor data, control unit status, etc. The following figure shows the DTC snapshot information related to engine control, including engine coolant temperature, throttle position, engine speed, vehicle speed, etc., as shown below:

source: ISO14229-1

These DTC snapshot information are recorded and stored in a prescribed manner, and can then be retrieved by sending a specific UDS request through the diagnostic instrument. In general, DTC snapshot information provides a detailed fault scene record, so that technicians can more accurately understand the vehicle status and parameters when the fault occurs during fault diagnosis and repair, analyze the data differences when the fault occurs, determine the potential source of the fault, and take appropriate repair measures.

It should be noted that
not all vehicles support or implement the DTC snapshot information in the ISO 14229 standard. Specific vehicle models and manufacturers may choose whether to support and provide the DTC snapshot information function based on their own needs and designs.