SERVICE MANUAL NUMBER 24
DIAGNOSTICS
Code 42 (2 of 2): Ignition Control (IC) Circuit
Step
Action
Yes
No
PROCEED TO
Was the “On-Board Diagnostic” (OBD) System Check
Performed?
1.
Step 2.
OBD
a. Clear trouble code 42.
b. Start engine and idle for 2 minutes or until trouble code
2.
3.
42
sets, whichever occurs first.
Is trouble code 42 present?
a. Ignition OFF.
Step 3. Step 11.
b. Disconnect ECM harness connectors.
c. Using a DVOM selected for Ohms, probe ECM harness
terminal CKT 423 to ground.
Is resistance over 3000 ohms?
Step 4. Step 7.
a. Leave DVOM connected from ECM harness terminal
CKT 423 to ground.
b. Using a test light connected to battery positive (B+),
probe ECM CKT 424.
4.
c. As the test light contacts CKT 424, the resistance
should switch from over 3000 Ohms to under 1000
Ohms.
Does the resistance switch to under 1000 ohms?
Step 11. Step 5.
Step 6. Step 8.
Using a test light connected to battery positive (B+),
probe ECM CKT 424.
5.
6.
7.
8.
Does test light illuminate?
Disconnect the ignition module 4-wire connector.
Does the test light illuminate?
Step 9. Step 10.
Step 10.
Locate and repair short to ground in CKT 423 or faulty
ECM connections.
Was a problem found?
Locate and repair open in CKT 424.
Was a problem found?
Verify
Step 10.
Repair
Locate and repair short to ground in CKT 424 or faulty
ECM connections.
9.
–
–
10.
Replace faulty ignition module.
Trouble code 42 is intermittent. Refer To “Diagnostic
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.
11.
–
–
Index
90-861327--1
OCTOBER 1999
Page 5G-77
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 305 CID, Mercury MerCruiser 350 CID |
| Model Year | 1998, 1999, 2000, 2001 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
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