98257 Mercruiser SCREW, (.312-18 x .500)

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SchematicTest Step 1. Inspect Electrical Connectors and Wiring
Remove the electrical power from the ECM.
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Typical left side view (1) J1/P1 ECM connector
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P1 ECM connector (P1-40) Engine start switch NO (P1-41) Engine start switch NC (P1-5) Return
Thoroughly inspect connector 1.
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Operator controls (steering console) (1) Engine start switch (2) Throttle
Thoroughly inspect connector 1 and thoroughly inspect the connector for switch 2. Refer to diagnostic functional tests Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on the wire in the ECM connector that is associated with the active event code.
Check the ECM connector (allen head screw) for the proper torque. Refer to diagnostic functional tests 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 are completely inserted and coupled. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The harness and wiring are OK. Proceed to Test Step 2.
Not OK - There is a problem in the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check the Status of the User Defined Shutdown Input on Caterpillar Electronic Technician (ET)
Verify that the electrical power is removed from the ECM.
Verify that the engine start switch is in the HOLD position.
Connect Cat ET to the service tool connector.
Restore the electrical power to the ECM. Do not start the engine.
Momentarily push up the engine start switch to the START position.
Observe the status of "User Shutdown" on Cat ET.
Momentarily push down the engine start switch to the STOP position.
Observe the status of "User Shutdown" on Cat ET.Note: Perform this test on both operator control panels.Expected Result:The status of the "User Shutdown" is "OFF" when the switch is in the STOP position. The status of the "User Shutdown" is "ON" when the switch is in the START position.Results:
OK - The status of the "User Shutdown" is correct.Repair: If the problem is intermittent, refer to diagnostic functional tests Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - The status of the "User Shutdown" is not correct for one of the switch positions. Proceed to Test Step 3.Test Step 3. Check the Harness between the Engine Start Switch and the ECM
Remove the electrical power from the ECM.
Disconnect the+Batt wire from the engine start switch.
Restore the electrical power to the ECM.
Momentarily push the engine start switch upward to the START position.
Observe the status of "User Shutdown" on Cat ET.
Use a suitable piece of wire to short the engine start switch +Batt wire to chassis ground.
Momentarily push the engine start switch upward to the START position.
Observe the status of "User Shutdown" on Cat ET.Expected Result:The status of the "User Shutdown" is "OFF" when the wire is not shorted to chassis ground. The status of the "User Shutdown" is "ON" when the wire is shorted to chassis ground.Results:
OK - The circuit for the "User Shutdown" is operating correctly. The harness wiring and ECM are OK.Repair: Replace the engine start switch.STOP
Not OK - The status of the "User Shutdown" was not correct for one of the test procedures. Proceed to Test Step 4.Test Step 4. Check the Operation of the ECM
Remove the electrical power from the ECM.
Disconnect the J1/P1 ECM connector. Remove the engine start switch +Batt wire from the ECM connector. Install a jumper wire with Deutsch sockets on each end into the socket for the engine start switch +Batt wire.
Reconnect ECM connector J1/P1.
Restore the electrical power to the ECM.
Momentarily push the engine start switch upward to the START position.
Observe the status of "User Shutdown" on Cat ET.
Use a suitable piece of wire to short the jumper wire in the socket for the engine start switch to chassis ground.
Observe the status of "User Shutdown" on Cat ET.Expected Result:The status of the "User Shutdown" is "OFF" when the jumper wire is not shorted to chassis ground. The status of the "User Shutdown" is "ON" when the jumper wire is shorted to chassis ground.Results:
OK - The ECM is responding to the input correctly.Repair: Repair the connectors or wiring and/or replace the connectors or wiring between the ECM and the customer shutdown switch.STOP
Not OK - The status of the "User Shutdown" is not correct.Repair: Verify your results. Replace the ECM. Refer to electronic troubleshooting Troubleshooting, "Replacing the ECM" before replacing the ECM.STOP