GENERAL SYSTEM DIAGNOSTICS SERVICE MANUAL NUMBER 23
Page 5E-54 90-861326--1 MARCH 1999
On-Board Diagnostic (OBD) System Check (Scan)
461 ORN/BLK
451 WHT/BLK
a
b
c
d
e
f
g
h
i
j
k
l
m
n
a-ECM/DLC 15amp fuse
b-DLC Connector
c-Marine Diagnostic Code Tool
d-ECM, Injector Knock Sensor Module 10amp Fuse
e-(ORN-Some Models)
f-(BLK-Some Models)
g-Serial Data
h-ECM Ground
i-ECM Ground
j-Diagnostic Test Terminal
k-Malfunction Indicator Lamp (MIL)
l-Ignition Feed
m-Battery Feed
n-Battery Feed
CIRCUIT DESCRIPTION:
The on-board diagnostic system check must be the starting point for any driveability com-
plaint diagnosis. Before using this procedure, you should perform a careful visual/physical
check of the ECM and engine
grounds for being clean and tight.
The on-board diagnostic system check is an organized approach to identifying a problem
created by an electronic engine control system malfunction.
DIAGNOSTIC AIDS:
An intermittent may be caused by a poor connection, rubbed through wire insulation or a
wire broken inside the insulation. Check for the following items:
• Inspect the ECM harness and connectors for improper mating, broken locks, improperly
formed or damaged terminals poor terminal to wire connection, and damaged harness.
Downloaded from https://needmanual.com/!
To Next Page
Loading...
Need help?
General