Diagnostic Mode 03 - Read DTC Memory: Notes
Diagnostic Mode 03 makes it possible to read emissions-related faults (confirmed DTCs: faults which have activated the MIL) in the ECM and in the TCM.
When the Engine Control Module (ECM) -- recognizes an emission related fault it turns on the Malfunction Indicator Lamp (MIL) -- or if a Electronic Throttle Malfunction is recognized, the Engine Control Module (ECM) -- turns on the Electronic Power Control (EPC) Warning Lamp -- which are both located in the instrument cluster.
The DTC's are sorted by SAE code with the DTC tables consisting of a 5-digit alpha-numeric value.
Depending on scan tool and protocol used, diagnostic mode 03 and the information provided may be referred to by a different name.
The following tables provide a breakdown and explanation of the DTC code.