MULTI-PORT FUEL INJECTION DESCRIPTIONS AND SYSTEM OPERATION
SERVICE MANUAL NUMBER 23
Intermittent Malfunction Indicator Lamp
In the case of an intermittent problem, the Malfunction Indicator Lamp will light for ten
seconds and then will go out. However, the corresponding code will be stored in the memory
of the ECM. When unexpected codes appear during the code reading process, one can
assume that these codes were set by an intermittent malfunction and could be helpful in
diagnosing the system.
An intermittent code may or may not reset. IF IT IS AN INTERMITTENT FAILURE, A DIAG-
NOSTIC CODE CHART IS NOT USED. Consult the “Diagnostic Aids” on the same page
as the diagnostic code chart. “Troubleshooting” also covers the topic of “Intermittents.” A
physical inspection of the applicable sub-system most often will resolve the problem.
Reading Codes
The provision for communicating with the ECM is the Data Link Connector (DLC) connector.
It is part of the EFI engine wiring harness, and is a 10-pin connector, which is electrically
connected to the ECM. It is used in the assembly plant to receive information in checking
that the engine is operating properly before it leaves the plant. The code(s) stored in the
ECM’s memory can be read either through a scan tool, (a diagnostic scanner that plugs into
the DLC connector), or by counting the number of flashes of the Malfunction Indicator Lamp
when the diagnostic code tool is installed and SERVICE mode is selected.
73053
DLC Connector
Once the diagnostic code tool has been connected, the ignition switch must be moved to
the ON position, with the engine not running. At this point, the Malfunction Indicator Lamp
should flash Code 12 three times consecutively. This would be the following flash sequence:
flash, pause, flash-flash, long pause, flash, pause, flash-flash, long pause, flash, pause,
flash-flash. Code 12 indicates that the ECM’s diagnostic system is operating. If Code 12 is
not indicated, a problem is present within the diagnostic system itself, and should be
addressed by consulting the appropriate diagnostic chart in “Diagnostics.”
Following the output of Code 12, the Malfunction Indicator Lamp will indicate a diagnostic
code three times if a code is present, or it will simply continue to output Code 12. If more
than one diagnostic code has been stored in the ECM’s memory, the codes will be output
from the lowest to the highest, with each code being displayed three times.
If a scan tool is used to read the codes, follow the manufacturer’s instructions.
Page 5B-8
90-861326--1 MARCH 1999
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 454 CID, Mercury MerCruiser 502 CID |
| Model Year | 1998, 1999, 2000, 2001 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
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