What does Mode 3 represent in the diagnostic modes?

Mode 3 in diagnostic modes is associated with the retrieval of stored Diagnostic Trouble Codes (DTCs). When a vehicle's onboard diagnostic system detects a malfunction, it stores a code that corresponds to the issue. This allows technicians to access the specific fault information that can assist with troubleshooting.

Stored DTCs provide valuable insights into past malfunctions that have been registered, making it easier to identify ongoing or recurring issues during the diagnostic process. Understanding these codes is crucial for effective vehicle repairs and ensuring that the emissions systems function correctly, which is a key part of smog repair.

The other modes have specific purposes as well. For instance, one might focus on clearing codes and resetting monitors while another could involve live data, which provides real-time readings of various parameters from the vehicle’s sensors. Freeze Frame Data captures a snapshot of the operating conditions when a fault was first detected, which can also be critical for diagnosis but does not pertain to the stored codes themselves.