SERVICE MANUAL NUMBER 23
TROUBLE CODE DIAGNOSTICS - 7.4L MPI
Code 41 (2 of 3): Ignition Control (IC) Circuit (Scan) Open IC Circuit
DIAGNOSTIC AIDS:
Check for the following conditions:
•
Poor connection at ECM. Inspect harness connectors for backed out terminals,
improper mating, broken locks, improperly formed or damaged terminals and poor ter-
minal to wire connection.
•
•
Damaged harness. Inspect the wiring harness for damage.
If the engine starts and stalls, it may set a false DTC 41 or 42. Clear DTC’s and repair
stalling condition.
After repairs, clear DTC’s following “Clearing Trouble Codes” procedure at the front of this
section. Failure to do so may result in DTC’s not properly being cleared.
TEST DESCRIPTION:
Step 2. DTC 41 means the ECM has seen an open in the IC circuit. This test confirms
DTC 41 and that the fault causing the DTC is present.
Step 3. Checks for a normal IC ground path through the Ignition Control (IC) module.
Step 4. Confirms that DTC 41 is a faulty ECM and not an intermittent open in CKT 423.
STEP
ACTION
VALUE
YES
NO
PROCEED TO
Go to
Was the “On-Board Diagnostic” (OBD) System
Check Performed?
OBD
System
Check
1
2
–
Step 2
1. Clear trouble code 41.
2.
Start engine and idle for 2 minutes or
until trouble code 41 sets.
Is trouble code 41 present?
1. Ignition “OFF”.
–
Step 3
Step 8
3
4
2.
3.
Disconnect ECM harness connectors.
Using a DVOM selected for Ohms, probe
3000
6000
Ohms
to
ECM harness terminal J2-23 to ground.
Is resistance within the specified value?
1. Reconnect ECM.
Step 4
Step 7
Step 5
Step 8
2.
Start engine and idle for 2 minutes or
trouble code 41 sets.
Is trouble code 41 present?
–
90-861326--1
MARCH 1999
Page 5G-59
| 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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