TROUBLE CODE DIAGNOSTICS - 7.4L MPI
SERVICE MANUAL NUMBER 23
Code 42 (3 of 3): Ignition Control (IC) Circuit (Scan) Grounded IC Circuit, Open
Bypass Circuit, or Grounded Bypass Circuit
STEP
ACTION
VALUE
YES
NO
PROCEED TO
Using a test light connected to battery positive
(B+), probe ECM harness terminal J2-24 (CKT
424).
5
Does test light illuminate?
–
–
Step 6
Step10
Step 9
Disconnect the ignition module 4-wire connec-
tor.
6
7
Does the test light illuminate?
Step 11
1. Reconnect ECM.
2.
Start engine and idle for 2 minutes or
until trouble code 42 sets.
Is trouble code trouble code 42 present?
–
–
Step 12 Step 13
Step 11
Locate and repair short to ground in CKT 423.
If a problem is found, repair as necessary. Was
a problem found?
8
Locate and repair open in CKT 424. Was a
problem found?
9
–
–
–
–
Step 11
Verify
Locate and repair short to ground in CKT 424.
Is action complete?
10
11
12
Repair
–
–
–
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” following. Check harness and con-
nectors for an intermittent open or short to
ground in CKT 424, or an intermittent short to
ground in CKT 423.
13
–
–
–
Page 5G-62
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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