Self-Diagnostic System: Introduction

PCM includes a self-diagnostic system. When a malfunction occurs, PCM will illuminate MIL located on instrument panel. When a problem is detected and light is turned on, a corresponding trouble code will be stored in PCM memory. Problems are recorded as hard failures or as intermittent failures.

There 4 DTC categories:

1. Type "A"
   
   Emissions related, turns on MIL the first time DTC sets.
2. Type "B"
   
   Emissions related, turns on MIL if fault is active for 2 consecutive driving cycles.
3. Type "C"
   
   Non-emissions related, does not turn on MIL, but will turn on SERVICE light.
4. Type "D"
   
   Non-emissions related, does not turn on MIL or SERVICE light.