Mercury MerCruiser MIE 7.4L MPI User Manual

SERVICE MANUAL NUMBER 23TROUBLE CODE DIAGNOSTICS - 454/502 MAG MPI & 8.2L MPI
Page 5F-16 90-861326--1 MARCH 1999
Code 42 (3 of 3): Ignition Control (IC) Circuit (Non-Scan) (Continued)
1. Ignition OFF.
2 Di t ECM J1 d J2 t
2. Disconnect ECM J1 and J2 connectors.
3 Ignition ON
3
3
.
Ignition
ON
.
4. Use DVOM with selector in the OHMS
–
Ste
p
4
Ste
p
5
3
UO OS
range.
5 P b ECM h t CKT 423
–
Ste
4
Ste
5
5. Probe E
C
M harness connector
C
KT 423
with DVOM to
g
round.
tOtogoud
It should read more than 3000 Ohms. Does it?
4
Probe ECM harness connector CKT 424 with a
test light connected to battery
p
ositive (B+).
–
Ste
p
13
Ste
p
6
4
test
light
connected
to
battery
ositive
(B+)
.
Is test light on?
–
Ste
13
Ste
6
5
Open CKT 423, faulty connection or faulty igni-
tion module.
– – –
6
With Ohmmeter connected to ECM harness
CKT 423 and ground (–), probe harness CKT
424 with test light connected to battery positive
(B+).
–
Ste
p
8
Ste
p
7
6
(B+)
.
As test light contacts CKT 424, resistance
should change from over 3000 Ohms to under
1000 Ohms.
Does it?
–
Ste
8
Ste
7
7
Disconnect distributor 4-way connector. Con-
nect Ohmmeter between CKT 423 and ground
(
–
).
–
Ste
p
9
Ste
p
10
7
()
.
Resistance should have gone high (open cir-
cuit).
Does it?
–
Ste
9
Ste
10
8
Reconnect ECM and idle engine for 1 minute
or until code 42 sets.
Does Code 42 Set?
– Step 11 Step 12
9
CKT 424 open, faulty connections, or faulty
ignition module.
– – –
10 CKT 423 shorted to ground. – – –
11 Faulty ECM. – – –
12
Code 42 is intermittent. Refer to “Diagnostic
Aids.”
– – –
13
Disconnect ignition module 4-way connector.
–
Ste
p
14
Ste
p
15
13
Is test light on?
–
Ste
14
Ste
15
14 CKT 424 shorted to ground. – – –
15 Faulty ignition module. – – –
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Index

Mercury MerCruiser MIE 7.4L MPI Specifications

General

Brand	Mercury
Model	MerCruiser MIE 7.4L MPI
Category	Engine
Language	English