Mercury MerCruiser MCM 454 Mag MPI Service Manual page 646

SERVICE MANUAL NUMBER 23
On-Board Diagnostic (OBD) System Check (Non-Scan)
Step
Index
90-861326--1 MARCH 1999
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Action
1. Ignition "ON," engine "OFF."
2. install Marine
Trouble Code (MDTC) tool and
switch it to "Normal Mode."
1
3. Observe the Malfunction Indica-
tor Lamp (MIL).
Is the MIL "ON"?
1. With Marine Diagnostic Trouble
Code Tool on "normal mode."
2. Ignition "ON," engine "OFF."
2
3. Observe the Malfunction Indica-
tor Lamp on the MDTC tool.
Does the MIL Flash DTC 12?
1. Switch Marine
Trouble Code Tool to "service
mode."
3 2. Ignition "ON," engine "OFF."
3. Observe the Malfunction Indica-
tor Lamp on the MDTC tool.
Does the MIL Flash DTC 12?
1. Switch MDTC tool to "Normal
Mode."
4 2. Attempt to start the engine.
Did The Engine
Continue To Run?
1. Ignition "ON," Engine "OFF."
2. Switch MDTC tool to "Service
5 Mode."
Are Any Additional
Stored?
Does A Customer Complaint Or
6 Driveability Problem Currently
Exist?
1. Ignition "ON," engine "OFF."
2. Check CKT 451 for a short to
ground.
7
3. If a problem is found, repair as
necessary.
Was A Problem Found?
Replace the ECM.
8
Is Action Complete?
Value(s)
Diagnostic
-
-
Diagnostic
-
-
Start And
-
DTC's
-
-
-
GENERAL SYSTEM DIAGNOSTICS
Yes No
Go to Step 2 Go to Chart A-1
Go to Step 7 Go to Step 3
Go to Step 4 Go to Chart A-2
Go to Step 5 Go to Chart A-3
Go to
applicable
DTC Chart
Go to Step 6
Refer to Refer to
"Symptoms" "Diagnostic
section Aids"
Repeat OBD
System
Go to Step 8
Check
Repeat OBD
System
-
Check
Page 5E-53