Self-Diagnostic System: Notes

SBM is equipped with a self-diagnostic system, which detects system Diagnostic Trouble Codes (DTCs) or abnormalities. When a malfunction occurs, SBM will store a DTC. See SBM DTC DEFINITIONS. Malfunctions are recorded as history/intermittent failures or as current failures. If a DTC occurs and then no longer exists, some DTCs will remain current until first ignition cycle. Other DTCs will become history when fault condition no longer exists.

A scan tool can be used to retrieve and clear DTCs. The scan tool also has several features that can be used to help locate an intermittent condition. When scan tool is used for system tests, it will display values actually seen or commanded by various systems (i.e., PCM, instrument cluster). This will usually include the following types of information:

• Analog Data Input - Displays analog input seen by system.
• Inputs/Outputs - Displays digital values as seen by system, and provides indication of whether input or output has cycled.
• Special Functions (Output Controls) - Allows for outputs of system to be set at a desired value (ON or OFF).
• Clear Codes - Will erase DTCs for system currently selected (if problem still exists in system, DTC may immediately reset).