The EBTCM performs system self-diagnostics, and can detect and often isolate system malfunctions. When a malfunction is detected the EBTCM sets a Diagnostic Trouble Code (DTC). The DTC represents the malfunction, turns on the Antilock and/or Car Icon (TCS indicator) indicators (in almost all instances), and may disable the ABS/TCS/Active Handling (if equipped with RPO JL4) functions as necessary for the duration of the ignition cycle.