Self-Diagnostic System: Notes

CAUTION: Electronic modules are sensitive to static electrical charges. Proper grounding of technician and workplace is essential to prevent damage.

NOTE: Diagnostic Trouble Code (DTC) tests are written specifically for use with GM Tech 2 scan tool. Generic scan tool can be used but may have limited functions. This article only covers the portion of those systems which relates to Body Control Module (BCM) system diagnosis.

Control modules are equipped with a self-diagnostic system which detects system abnormalities. When a malfunction occurs, control module will store a DTC. Malfunctions are recorded as current and/or history (intermittent) failures. Current DTCs indicate control module has detected a fault which is currently present. A history DTC indicates that control module has previously detected a malfunction that is not currently present.