Mercury MerCruiser MCM 502 Mag MPI User Manual

GENERAL SYSTEM DIAGNOSTICS
SERVICE MANUAL NUMBER 23
90-861326--1 MARCH 1999 Page 5E-41
MEFI 3 - ECM J-1 and J-2 Circuit/Symptom Chart
In the following J-1 and J-2 Circuit/Symptom Charts only those pins which are used by the
ECM are shown. Pin numbers not listed are not used.
The “B+” Symbol indicates a system voltage (battery).
IMPORTANT: The following conditions must be met before testing.
1. Engine at operating temperature.
2. Ignition on or engine running.
3. Scan tool not connected.
J-1 Circuits
Pin
Circuit
(CKT)
Wire
Normal Voltage
Diag-
nostic
Possible
Pin
Func-
tion
Num-
ber
(#)
Wire
Color
Ignition
ON
Engine
Running
Trouble
Codes
DTC(s)
Possible
Symptoms
J1-1
Injector
Driver
467
DK
BLU
B+ B+ None
Rough Idle, Lack Of Power,
Stalling
J1-3
Ignition
Control
Ref.
Low
453
RED/
BLK
0
(NOTE 5)
0
(NOTE 5)
None Poor Performance
J1-4
ECM
Ground
450 BLK
0
(NOTE 5)
0
(NOTE 5)
None No Start
J1-5
ECM
Ground
450 BLK
0
(NOTE 5)
0
(NOTE 5)
None No Start
J1-9
MIL
Lamp
419
BRN/
WHT
0
(NOTE 5)
0
(NOTE 5)
None Lamp Inoperative
J1-10
Ignition
Control
Signal
423 WHT
0
(NOTE 5)
1.2V 42
Stall, Will Restart In Bypass
Mode, Lack Of Power
J1-11
IAC “B”
Low
443
GRN/
WHT
Not
Usable
Not
Usable
None Rough Unstable or Incorrect Idle
J1-12
IAC “A”
Low
442
BLU/
BLK
Not
Usable
Not
Usable
None Rough Unstable or Incorrect Idle
NOTE 1: Battery voltage for first two seconds, then 0 volts.
NOTE 2: Varies with temperature.
NOTE 3: Varies with manifold vacuum.
NOTE 4: Varies with throttle movement.
NOTE 5: Less than .5 volt (500 mV).
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Index

Mercury MerCruiser MCM 502 Mag MPI Specifications

General

Brand	Mercury
Model	MerCruiser MCM 502 Mag MPI
Category	Engine
Language	English