System Diagnosis: Notes

NOTE: PCM diagnostic memory is retained by direct power supply from battery. Memory is not erased by turning off ignition, but it will be erased if battery or PCM is disconnected.

System diagnosis can be accomplished using a scan tool on all models. The Malfunction Indicator Light (MIL) can also be used. See ENTERING ON-BOARD DIAGNOSTICS . Powertrain Control Module (PCM) monitors several different engine control system circuits. If an abnormal input signal occurs, a Diagnostic Trouble Code (DTC) is stored in PCM 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, PCM will turn on MIL. System failures encountered are identified as either hard failures or intermittent failures as determined by PCM.