TROUBLE CODE DIAGNOSTICS - 7.4L MPI
SERVICE MANUAL NUMBER 23
Code 41 (1 of 3): Ignition Control (IC) Circuit (Scan) - Open IC Circuit
“
C”
h
“+”
n
s
o
g
a
p
i
b
c
902
o
RED
PNK
j
k
l
t
3
d
q
r
n
121
121
GRY
WHT
m
f
o
e
a - Ignition coil connector
b - Distributor
c - To system relay
d - Ignition coil
e - Distributor
f - In-line harness (tach)
g - Ignition control module
h - Pick-up coil
i - Distributor 4 terminal connector
j - Ignition control (IC)
k - Dist. reference “high”
l - Bypass
m - Dist. reference “low”
n - Black Connector
o - Gray Connector
p - Tachometer
q - Secondary
r - Primary
s - Ignition
CIRCUIT DESCRIPTION:
When the system is running on the ignition module or crank mode, no voltage on the bypass
line, the ignition module grounds the IC signal. The ECM expects to detect a low voltage on
the IC line during this condition. If the ECM sees voltage, it sets Code 41 and will not go into
the IC mode.
When the RPM for IC is reached (about 300 RPM), and bypass voltage applied, the IC
should no longer be grounded in the ignition module, so the IC voltage should be varying.
If the bypass line is open or grounded, the ignition module will not switch to IC mode. The
IC line, CKT 423 voltage will be low and Code 42 will be set.
If CKT 423 is grounded, the IC module will switch to IC mode but, because the line is
grounded, there will not be an IC signal and a trouble code 42 will be set.
Page 5G-58
90-861326--1 MARCH 1999
| 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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