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