TROUBLE CODE DIAGNOSTICS - 7.4L MPI SERVICE MANUAL NUMBER 23
Page 5G-26 90-861326--1 MARCH 1999
DIAGNOSTIC AIDS:
Check for the following conditions;
• Poor connections at ECM. Inspect harness connectors for backed out terminals,
improper mating, broken locks, improperly formed or damaged terminals, and poor
terminal to wire connections.
• Damaged harness. Inspect the wiring harness for damage.
• If the engine starts and stalls, it may set a false trouble code 41. Clear trouble codes and
repair stalling condition.
TEST DESCRIPTION:
Step 2. Trouble code 41 means the ECM has seen an open in the IC circuit. This test con-
firms trouble code 41 and that the fault causing the trouble code is present.
Step 3. Check for a normal IC ground path through the IC module.
Step 4. Confirms that trouble code 41 is a faulty ECM and not an intermittent open in CKT
423.
Code 41 (2 of 3): Ignition Control (IC) Circuit (Non-Scan) - Open IC Circuit
STEP ACTION VALUE YES NO
PROCEED TO
1
Was the “On-Board Diagnostic” (OBD) System
Check Performed?
– Step 2
Go to
OBD
System
Check
2 1.Install Marine Diagnostic Code Tool.
2. Clear trouble code 41.
3. Start engine and idle for 2 minutes or Ma-
rine Diagnostic Code Tool indicates a stored
trouble code.
4. Ignition “ON,” engine “OFF.”
7. Switch Marine Diagnostic Code Tool to
“Service Mode” and note trouble code.
Is trouble code 41 present?
– Step 3 Step 8
3 1. Ignition “OFF.”
2. Disconnect ECM harness connectors.
3000 to
3. Using a DVOM set on OHMS, probe
ECM harness terminal J2-23 to ground.
6000
Ohms
Is resistance within specified value?
Step 4 Step 5
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