When retrieving diagnostic trouble codes (DTCs) from the PCM, which steps should be followed?

When retrieving diagnostic trouble codes (DTCs) from the Powertrain Control Module (PCM), it is essential to follow a systematic approach to ensure that valuable information is not overlooked. The correct approach involves recording the DTCs and reviewing the freeze frame data before clearing the codes.

Recording the DTCs allows you to document the specific issues identified by the PCM. This information can be critical for diagnosing the root cause of the problem, as it provides insight into what the vehicle was experiencing at the time the fault occurred. Freeze frame data adds another layer of context by capturing key parameters (such as engine speed, vehicle speed, temperature, etc.) at the moment the DTC was set. This data can be essential for understanding the conditions that led to the fault, which can help in troubleshooting and effectively repairing the vehicle.

After these steps have been taken, clearing the codes can be performed to reset the PCM, which allows for monitoring the systems in a "fresh" state to see if the issue returns. However, clearing the DTCs before recording them would mean losing the specific details that could help guide the diagnosis. Performing a visual inspection is still a valuable step, but it should follow the recording of DTCs and review of freeze frame