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On Board Diagnostic (OBD) System: Introduction

The ECM has an on board diagnostic system, which detects malfunctions related to engine sensors or actuators. The ECM also records various emission-related diagnostic information including:

DTC REFERENCE CHART

Emission-related diagnostic information Diagnostic service
Diagnostic Trouble Code (DTC) Service $03 of SAE J1979
Freeze Frame data Service $02 of SAE J1979
System Readiness Test (SRT) code Service $01 of SAE J1979
1st Trip Diagnostic Trouble Code (1st Trip DTC) Service $07 of SAE J1979
1st Trip Freeze Frame data -
Test values and Test limits Service $06 of SAE J1979
Calibration ID Service $09 of SAE J1979
DTC REFERENCE CHART

The above information can be checked using procedures listed in the table below.
x: Applicable -: Not applicable
  DTC 1st trip DTC Freeze Frame data 1st trip Freeze Frame data SRT code SRT status Test value
CONSULT-III x x x x x x -
GST x x x - x x x
ECM x x(1) - - - x -
(1) When DTC and 1st trip DTC simultaneously appear on the display, they cannot be clearly distinguished from each other.

The malfunction indicator lamp (MIL) on the instrument panel illuminates when the same malfunction is detected in two consecutive trips (Two trip detection logic), or when the ECM enters fail-safe mode. (Refer to "FAIL-SAFE CHART ".)