Diagnostic Trouble Codes (DTCS)
If the control module detect a fault, a diagnostic trouble code (DTC) is stored. A fault that was detected during the last operating cycle is defined as permanent. Other faults that are detected are defined as intermittent.
Should a fault disappear for any reason after being stored in the control module as a permanent diagnostic trouble code, the information remains stored in the control module. If a fault is no longer permanent, the diagnostic trouble code remains as intermittent.