GENERAL SYSTEM DIAGNOSTICS
SERVICE MANUAL NUMBER 23
Page 5E-56
90-861326--1 MARCH 1999
On-Board Diagnostic (OBD) System Check (Scan)
Step
Action
Value(s)
Yes
No
1
1. Ignition “ON,” engine “OFF.”
2. Install Marine Diagnostic
Trouble Code (MDTC) tool and
switch it to “Normal Mode.”
3. Observe the Malfunction Indica-
tor Lamp (MIL).
Is the MIL “ON”?
-
Go to Step
2
Go to
Chart A-1
2
1. Ignition “OFF.”
2. Install a scan tool.
3. Ignition “ON.”
4. Attempt to display ECM data
with the scan tool.
Does The Scan Tool Display ECM
Data?
-
Go to Step 3
Go to Step
7
3
Attempt to start the engine.
Did The Engine Start And
Continue To Run?
-
Go to Step
4
Go to
Chart A-3
4
Select “Display DTCs” with the scan
tool.
Are Any Trouble Codes Stored?
-
Go to
applicable
DTC Chart
Go to Step
5
5
Compare ECM data values
displayed on the scan tool to the
typical scan tool data values page.
Are The Displayed Values Normal
Or Close To The Typical Values?
-
Refer to
“Trouble-
shooting”
section
Refer to
“Diagnostic
Testing”
6
1. Ignition “OFF.”
2. Disconnect the ECM.
3. Check the serial data CKT 461
for an open, short to ground, or
short to voltage. Also, check the
DLC battery feed circuit for an
open or short to ground and the
DLC ground CKT 450 for an
open.
4. If a problem is found, repair as
necessary.
Was A Problem Found?
-
Repeat OBD
System
Check
Go to Step 7
7
Replace the ECM.
Is Action Complete?
-
Repeat OBD
System
Check
-
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