863012T 1 Mercruiser PIPE, Exhaust ( Bull Horn )

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SchematicTest Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF/RESET position.
Thoroughly inspect ECM connector J2/P2, machine connector J3/P3, and the connection to the user defined shutdown device (switch). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and wiring for abrasion and for pinch points from the user defined shutdown device to the ECM.Expected Result:All connectors, pins, and sockets should be completely inserted and coupled. The harness and wiring should be free of corrosion, abrasion, and pinch points.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 2. Check the Status on ET
Connect ET to the service tool connector.
Turn the keyswitch to the ON position.
Observe the status of "User Shutdown" on ET.Expected Result:The status should be "Off".Results:
OK - Proceed to Test Step 3.
Not OK - Proceed to Test Step 4.Test Step 3. Short the Input at the Machine Connector
Use a suitable piece of wire to short J3:12 User Defined Shutdown to chassis ground.
Observe the status of "User Shutdown" on ET.Expected Result:The status should be "On" when the terminal is grounded.Results:
OK - The circuit from machine connector J3 to the ECM is functioning properly. A problem may exist in either the user defined shutdown device (switch) or the circuit between the switch and machine connector P3.Repair: Troubleshoot the circuit between machine connector P3 and the switch. Repair the circuit and/or replace the switch, as needed.STOP
Not OK - Proceed to Test Step 4.Test Step 4. Check the Harness for Shorts
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ECM connector P2 (ECM side)
Disconnect ECM connector J2/P2.
Measure the resistance between P2:1 (User Defined Shutdown) and engine ground.Expected Result:The resistance should be greater than 20,000 Ohms.Results:
OK - Proceed to Test Step 5.
Not OK - There is a short circuit in the harness or a user defined shutdown device is activating the shutdown feature.Repair: Ensure that a user defined shutdown device is not activating the shutdown feature.Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 5. Check the Resistance through the Harness
Illustration 3 g00713522
ECM connector P2 (ECM side)
Turn the keyswitch to the OFF/RESET position.
Disconnect ECM connector J2/P2.
Use a suitable piece of wire to short J3:12 User Defined Shutdown to chassis ground.
Measure the resistance between P2:1 (User Defined Shutdown) and engine ground.
Remove the wire short.Expected Result:The resistance should be less than 10 Ohms when the terminal is grounded.Results:
OK - The resistance is within acceptable limits. Proceed to Test Step 6.
Not OK - There is an open circuit or excessive resistance in the harness.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 6. Short the Input at the ECM
Illustration 4 g00713522
J2/P2 breakout
Turn the keyswitch to the OFF/RESET position and install a 7X-1715 Adapter Cable (40 Pin Breakout) at ECM connector J2/P2.
Turn the keyswitch to the ON position.
Observe the status of "User Shutdown" on ET.
Use a suitable piece of wire to short P2:1 (User Defined Shutdown) to engine ground.
Observe the status of "User Shutdown" on ET.Expected Result:The status should be "On" when the wire short is in place. The status should be "Off" when the wire short is removed.Results:
OK - The shutdown feature is working properly.STOP
Not OK - The correct switch input appears at the ECM, but the ECM is not reading the switch input properly.Repair: Verify your results. Replace the ECM. Refer to Troubleshooting, "Replacing the ECM" before replacing the ECM.STOP