GENERAL SYSTEM DIAGNOSTICS
SERVICE MANUAL NUMBER 23
90-861326--1 MARCH 1999 Page 5E-7
MEFI 3 - Codes for the 454 cid (7.4L) / 502 cid (8.2L) Engines (continued)
Code
Number
Connection Conditions Comments
45 Coil driver fault
Ignore first 20 spark events requires
8 faults to set code
Open secondary
wire
Open primary cable
51 Checksum error Reserved - Invalid ECM checksum Bad ECM
61
Fuel pressure
high
Minimum run time (10 sec)
Sensor output high (> 4.9 volts)
Open circuit
Faulty sensor
Bad/wrong regulator
62
Fuel pressure
low
Minimum run time (10 sec)
Sensor output low (< 0.1 volts)
Short circuit
Faulty sensor
No fuel pump power
Special Tools
Part Number Tool Name Description
J-34029-A (Note 1)
High Impedance
Multimeter (DVM)
Minimum 10 megohm input impedance
required on all voltage ranges. As amme-
ter, accurately measures low value current
flow. As ohmmeter, reads 0-200 ohms,
2/20/200 kΩ, 2/20 mΩ
J-23738
Vacuum Pump with
Gauge - 20 In. Hg
Minimum
Gauge monitors manifold engine vacuum.
Hand pump used to check fuel pressure
regulator
J-34142-B (Note 2)
Unpowered Test
Light
Used to check circuit wiring, short to
ground, or voltage.
91-99379 Timing Light
Used to check ignition timing. Must have
inductive signal pickup.
91-16850A1
Fuel Pressure
Gauge
Used to check fuel system pressure.
J-34730-2A
Injector Harness
Test Light
Visually indicates injector electrical im-
pulses from the ECM.
91-823686A2
Quicksilver Scan
Tool
Displa
s problem codes stored in the
84-822560A2
MERCRUISER
Cable
ECM. It also allows monitoring of various
circuits and components in the fuel injec-
91-861538
MERCRUISER Car-
tridge
on sys
em.
94040M
EFI Scan Tool/Injec-
tor Tester
(Rinda Technolo-
gies)
Displays problem codes stored in the
ECM. It also allows monitoring of various
circuits and components in the fuel injec-
tion system. Allows for test firing injectors.
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