Self-Diagnostic System: Notes

ECM/PCM monitors several different circuits of engine control system. If a problem is sensed with a monitored circuit, PCM will store a Diagnostic Trouble Code (DTC) to aid technician in diagnosis of system. A scan tool is used to read DTCs. Malfunction Indicator Light (MIL) may also be used to read DTCs on some vehicles. For additional information, see appropriate SELF-DIAGNOSTICS article.