Mercury MerCruiser MCM 454 Mag MPI Service Manual page 657

GENERAL SYSTEM DIAGNOSTICS
Chart A-2 (3 of 3): Malfunction Indicator Lamp "On" Steady - No DLC Data or
Will Not Flash DTC 12 - Marine Diagnostic Trouble Code (MDTC) Tool Installed
Step
1
2
3
4
5
6
7
8
9
Index
Page 5E-64
Downloaded from https://needmanual.com/
Action
Was the "On-Board Diagnostic"
(OBD)
System Check Performed?
1. Ignition "ON," engine "OFF."
2. Switch MDTC tool to "Service
Mode."
Does The MIL Flash DTC 12?
1. Ignition "OFF," disconnect
ECM connectors.
2. Ignition "ON," engine "OFF,"
observe the MIL.
Is The MIL "ON"?
1. Ignition "OFF."
2. With ECM "J1" connector dis-
connected, jump terminals "A"
to "B" at the DLC.
3. Connect test light between
ECM connector terminal "J1-7"
and battery positive (B+).
Does Test Light Illuminate
Brightly?
1. Verify correct operation of
MDTC tool on a known good
system.
2. If a problem is found, repair as
necessary.
Is Action Complete?
1. If problem was no DLC data
(using scan tool), check
serial data CKT 461 for an
open or short to ground.
2. If a problem is found, repair as
necessary.
Is Action Complete?
Locate and repair short to ground
in CKT 419.
Is Action Complete?
Locate and repair open in CKT 450
and/or CKT 451.
Is Action Complete?
1. Repair faulty ECM connections
or replace faulty ECM.
2. Recheck for DTC 12.
Is Action Complete?
SERVICE MANUAL NUMBER 23
Value(s) Yes
-
Go to Step 2
-
Go to Step 6
-
Go to Step 7
-
Go to Step 5
_
Go to OBD
System Check
-
Go to OBD
System Check
-
Go to OBD
System Check
-
Go to OBD
System Check
_
Go to OBD
System Check
90-861326--1 MARCH 1999
No
Go to OBD
System Check
Go to Step 3
Go to Step 4
Go to Step 8
Go to Step 9
Go to Step 9
_
_
_