TROUBLE CODE DIAGNOSTICS - 7.4L MPI
SERVICE MANUAL NUMBER 23
Code 42 (3 of 3): Ignition Control (IC) Circuit (Non-Scan) - Grounded IC Circuit,
Open Bypass Circuit, or Grounded Bypass Circuit
STEP
ACTION
VALUE
YES
NO
PROCEED TO
3
1. Ignition “OFF.”
2.
3.
ECM harness terminal J2-23 to ground.
Disconnect ECM harness connectors.
Using a DVOM set on OHMS, probe
3000
6000
Ohms
to
Is resistance within specified value?
Step 4
Step 8
1.
ness terminal J2-23 to ground.
Leave DVOM connected from ECM har-
4
2.
Using a test light connected to battery
positive (B+), probe ECM harness terminal
J2-24.
1000
Ohms
3.
As the test light contacts J2-24, the resis-
tance should switch from 3000 Ohms to under
1000
Ohms.
Does the resistance switch to under the
specified value?
Step 7
Step 6
Step 5
Step 9
Using a test light connected to battery positive
(B+), probe ECM harness terminal J2-24
(CKT424).
5
Does light illuminate?
–
–
6
7
Disconnect ignition module 4-way connector.
Does test light illuminate?
Step 10 Step 11
1.
2.
Reconnect ECM.
Start engine and idle for 2 minutes or Ma-
rine Diagnostic Code Tool indicates a stored
trouble code.
–
–
Step 12 Step 13
Step 11
Is trouble code 42 present?
Locate and repair short to ground in CKT 423.
If a problem is found, repair as necessary. Was
a problem found?
8
9
Locate and repair open CKT 424. If a problem
is found, repair as necessary. Was a problem
found?
–
Step 11
Verify
Locate and repair short to ground in CKT 424.
Is action complete?
Repair
10
11
12
–
–
–
–
Replace faulty ignition module. Is action com-
plete?
–
–
Repair faulty ECM connections or replace
faulty ECM. Is action complete?
Trouble code 42 is intermittent. Refer to “Diag-
nostic Aids” on facing page. Check harness
and connectors for an intermittent open or
short to ground in CKT 424, or an intermittent
short to ground in CKT 423.
13
–
–
–
Page 5G-30
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 |
(1 votes, average: 5 out of 5)
Marine readers have rated Mercury MerCruiser GM V8 GM V8 454 CID 7.4L and 502 cid 8.2L Marine Engines Service Manual Number 23 5.0 out of 5.0 based on 1 product reviews. Just need the manual. Wrote review. Can't technically review what I haven't seen yet...