Self-Diagnostic System: Introduction

1995 Saturn SL1 AutomaticSECTION Introduction
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 1996 Saturn SW2, 1996 Saturn SW1, 1996 Saturn SL2, 1996 Saturn SL1, and 1996 Saturn SC2. However, it is still accessible from the selected car via links, so may be relevant.

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.

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.