Code 51: Calibration Memory Failure Non-Scan Diagnostics
(1 of 2)
72801
CIRCUIT DESCRIPTION:
DIAGNOSTIC AIDS:
This test allows the ECM to check for a calibration
failure by comparing the calibration value to a known
value stored in the EEPROM.
An intermittent Code 51 may be caused by a bad cell
in the EEPROM that is sensitive to temperature
changes. If Code 51 failed more than once, but is in-
termittent, replace ECM.
This test is also used as a security measure to pre-
vent improper use of calibrations or changes to these
calibrations that may alter the designed function of
the EFI system.
An intermittent problem may be caused by a poor or
corroded connection, rubbed through wire connec-
tion, a wire that is broken inside the insulation, or a
corroded wire.
TEST DESCRIPTION:
Any circuitry that is suspected as causing the inter-
mittent complaint should be thoroughly checked for
backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, corroded terminals
and/or wiring, or physical damage to the wiring har-
ness. After repairs, clear codes following “Clearing
Codes” in “ECM Self-Diagnostics.” Failure to do so
may result in codes not properly being cleared.
Number(s) below refer to circled number(s) on the
diagnostic chart.
1.
This step checks to see if the fault is present dur-
ing diagnosis. If present, the ECM is not function-
ing correctly and must be replaced.
IMPORTANT: At the time of printing, vessels with
Fuel Injection were not being field repro-
grammed to correct this failure. Replacement of
the ECM with a factory reprogrammed ECM is
necessary if Code 51 is current and resets when
clearing codes is completed.
Index
5C-98 - ELECTRONIC FUEL INJECTION (MULTI-PORT AND THROTTLE BODY)
90-823224--2 796
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 454 CID, Mercury MerCruiser 502 CID |
| Model Year | 1993, 1994, 1995, 1996, 1997 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
(4 votes, average: 4.5 out of 5)
Marine readers have rated 1993 1997 Mercury-MerCruiser GM V8 454 CID 7.4L and 502 CID 8.2L Marine Engines Service Manual Number 16 4.5 out of 5.0 based on 4 product reviews. Hugely helpful service manual! Perfect. Thank you!
Manuals are all Important for Technician
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