Engines - Mercury MerCruiser MCM 454 Mag MPI Service Manual

GENERAL SYSTEM DIAGNOSTICS
MEFI 3 - Codes for the 454 cid (7.4L) / 502 cid (8.2L) Engines
Code
Number
14
15
21
22
23
25
33
34
41
42
43
44
Index
Page 5E-6
Downloaded from https://needmanual.com/
Connection
Minimum run time (10 sec)
ECT high
Sensor output high (cold) > 240
counts
Minimum run time (10 sec) sensor
ECT low
Sensor output low (hot) < 7 counts
Sensor output high (> 250 counts)
anytime or, skewed high ( > 70) @ <
TPS high
700 rpm and < 70 kpa for at least 5
seconds
Sensor output low (< 4 counts)
TPS low
anytime
Minimum run time (10 sec)
MAT high
Sensor output high (cold) > 253
counts
Minimum run time (10 sec) sensor
MAT low
Sensor output low (hot) < 7 counts
kpa > 80 and tps < 5% and rpm >
MAP high
500 for at least 5 seconds
kpa < 14 and tps > 5% and rpm
MAP low
<300 for at least 0.5 seconds
EST open (GM Ignore first 20 spark events requires
distributor only) 10 faults to set code
Ignore first 20 spark events requires
EST grounded
10 faults to set code
Continuous Must have continuous knock retard
knock for at least 30 seconds
After 513 tdc knock free events, rpm
No knock
> 3000 and MAP > 70 and filtered
sensor noise < 0.14 volts
SERVICE MANUAL NUMBER 23
Conditions
90-861326--1 MARCH 1999
Comments
Open circuit
Faulty sensor
Short circuit
Faulty sensor
Open circuit,
WOT Faulty sensor
No reference
ground
Short circuit
Faulty sensor
No reference
voltage
Open circuit
Faulty sensor
Short circuit
Faulty sensor
Open circuit
Faulty sensor
No Reference
ground
Short circuit
Faulty sensor
No reference
voltage
Open circuit
Faulty ignition
module
Short circuit
Faulty reference
pickup
Incorrect base
timing
Faulty knock sensor
Disconnected
sensor
Broken/open circuit
Faulty knock sensor