Mefi 2 - 7.4L Mpi Symptom Chart (J-1 Circuits) - Mercury MerCruiser MCM 454 Mag MPI Service Manual

GENERAL SYSTEM DIAGNOSTICS

MEFI 2 - 7.4L MPI Symptom Chart (J-1 Circuits)

Pin
J1-1
J1-2
J1-3
J1-4
J1-5
J1-6
J1-7
J1-8
Index
Page 5E-26
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Circuit
Pin Pin (CKT) (CKT) Wire Wire
Color Ignition
Function Number
(#)
Knock
485 GRN
Sensor
Signal
ECT
410 YEL
Signal
Not Used –
Discrete
911 BRN
Switches
Master/
916 YEL
Slave
Discrete
911 BRN
Switches
Diagnos- BLK/
451
tic Test WHT
Not Used –
Normal Voltage
Engine
ON Running
9.5V 9.5V
1.95V 1.95V
(NOTE 2) (NOTE 2)
– – –
– –
B+ B+
– –
B+ B+
– – –
SERVICE MANUAL NUMBER 23
Diagnostic
Tro ble Trouble Possible Possible
Codes Symptoms
DTC(s)
Poor Fuel
Economy,
43
Poor Perfor-
mance Deto-
nation
Poor Perfor-
mance, Ex-
haust Odor,
14
Rough Idle
RPM Reduc-
tion
– –
Audio Warn-
ing Activated
(Low Oil
Pressure/
Low I/O
None Fluid/Trans-
mission
Fluid/Over-
heat) Note:
Earlier Mod-
els Use J1-4
Lack Of
Data From
Other En-
None
gine (Dual
Engine
Only)
Audio Warn-
ing Activated
(Low Oil
Pressure/
Low I/O
None Fluid/Trans-
mission
Fluid/Over-
heat) Note:
Later Mod-
els Use J1-6
Incorrect
None
Idle, Poor
Performance
– –
90-861326--1 MARCH 1999