The Importance of Freeze Frame Data in Vehicle Diagnostics

What is freeze frame data and why is it important in vehicle diagnostics?

Technician A says erasing the code with a scan tool will erase the corresponding freeze frame data. Technician B says the freeze frame data is the sensor and output status data at the instant the DTC was set. Who is correct?

Answer:

Technician B is correct.

Freeze frame data refers to the sensor and output status data captured at the moment a Diagnostic Trouble Code (DTC) is set in a vehicle's onboard computer system. It provides crucial information about the operating conditions that led to the detection of the fault. The freeze frame data allows technicians to understand the specific circumstances under which the DTC occurred, aiding in the diagnosis and troubleshooting process.

When a DTC is stored, the corresponding freeze frame data is also stored alongside it. This freeze frame data helps technicians analyze the problem by providing a snapshot of the vehicle's condition at the time the DTC was triggered. It includes information such as engine speed, coolant temperature, vehicle speed, throttle position, and other relevant sensor readings.

Technician A's statement is incorrect because erasing the code using a scan tool does not automatically erase the freeze frame data. The scan tool is used to clear the stored DTCs from the vehicle's computer system, but the freeze frame data remains intact. This allows technicians to review the freeze frame data even after the DTC has been cleared, helping them to identify patterns or recurring issues.

In summary, freeze frame data is a valuable diagnostic tool that provides a snapshot of the vehicle's operating conditions at the time a DTC is triggered. It assists technicians in understanding the circumstances surrounding the fault and facilitates accurate diagnosis and repair. Erasing the DTC with a scan tool does not erase the corresponding freeze frame data, allowing technicians to access and analyze it for diagnostic purposes.