Mercury MerCruiser MCM 454 Mag MPI Service Manual page 650

SERVICE MANUAL NUMBER 23
Chart A-1 (1 of 4): No Malfunction Indicator Lamp (MIL) -
Marine Diagnostic Trouble Code (MDTC) Tool Installed
CIRCUIT DESCRIPTION:
When the Marine Diagnostic Trouble Code (MDTC) tool is installed, it plugs into the DLC
terminals "F" and "E". It receives voltage through CKT 440 terminal "F"
ground through CKT 419 from the ECM terminal "J2-31". There should always be a steady
MIL with the ignition "ON" and the engine stopped. The Engine Control Module (ECM) turns
the MIL"ON" by grounding the MIL driver circuit.
Index
90-861326--1 MARCH 1999
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b
a
c
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
l - Ignition Feed
m - Battery Feed
n - Battery Feed
e
461 ORN/BLK
f
451 WHT/BLK
d
GENERAL SYSTEM DIAGNOSTICS
g
h
i
j
k
l
m
n
Terminal "E" is
s
Page 5E-57