System Diagnosis: Notes

System diagnosis can be accomplished using a scan tool on all models. See ENTERING ON-BOARD DIAGNOSTICS  . Powertrain Control Module (ECM) monitors several different engine control system circuits. If an abnormal input signal occurs, a Diagnostic Trouble Code (DTC) is stored in ECM memory and assigned a DTC number. Each circuit has its own DTC number and message. A specific DTC indicates a particular system failure, but does not indicate that cause of failure is necessarily within system.

A DTC does not condemn any specific component; it simply points out a probable malfunctioning area. If a DTC is set, ECM will turn on MIL. System failures encountered are identified as either hard failures or intermittent failures as determined by ECM.