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 ECM recognizes an emissions-related fault in two consecutive drive cycles, it sends a request to the instrument cluster over the CAN to turn on the malfunction indicator lamp. If an electronic throttle malfunction is recognized, the ECM will send a request to the instrument cluster over the CAN to turn on the electronic power control warning lamp.
The DTCs are sorted by SAE code with the DTC tables consisting of a 5-digit alphanumeric value.
Depending on the 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.