845942 Mercruiser SCREW, (.312-18 x .750)

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Schematic
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P2 ECM connector
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P1 ECM connector
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Sensor connectorTest Step 1. Check for Active +5 V Sensor Supply Diagnostic Codes
Connect the Caterpillar Electronic Technician (Cat ET) to the service tool connector.
Turn the keyswitch to the ON position. Wait at least 15 seconds for activation of the diagnostic codes.
Verify that neither of the following diagnostic codes are active:
262-03 5 Volt Sensor DC Power Supply short to +batt
262-04 5 Volt Sensor DC Power Supply short to groundExpected Result:Neither of the preceding diagnostic codes are active.Results:
OK - The diagnostic codes are not active. Proceed to Test Step 2.
Not OK - One of the diagnostic codes is active.Repair: Perform the following diagnostic procedure: Troubleshooting, "5 Volt Engine Pressure Sensor Supply Circuit - Test".STOPTest Step 2. Inspect Electrical Connectors And Wiring
Thoroughly inspect the J1/P1 ECM connector, the J2/P2 ECM connector, and any connectors that are associated with the suspect pressure sensor. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and the sensor connectors that are associated with the active diagnostic code.
Check the ECM connector (allen head screw) for the proper torque of 6.0 N m (55 lb in).
Check the harness and wiring for abrasion and for pinch points from the sensors back to the ECM.Expected Result:All connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The connectors and the wiring appear to be OK. Proceed to Test Step 3.
Not OK - There is a problem with the connectors and/or the 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.Clear all logged diagnostic codes.STOPTest Step 3. Determine the Condition that is Present
Turn the key switch to the ON position. Wait at least 15 seconds for activation of the diagnostic codes.
Monitor the active diagnostic code screen on Cat ET.
Determine if the problem is related to an open circuit diagnostic code or to a short circuit diagnostic code.Expected Result:Either an open circuit diagnostic code or a short circuit diagnostic code is active.Results:
Short Circuit - A short circuit diagnostic code is active at this time. Proceed to Test Step 4.
Open Circuit - An open circuit diagnostic code is active at this time. Proceed to Test Step 7.Test Step 4. Disconnect the Suspect Sensor
Turn the keyswitch to the OFF position.
Disconnect the sensor with the short circuit diagnostic code.
Turn the keyswitch to the ON position. Wait at least 15 seconds for activation of the diagnostic codes.
Check for an active open circuit diagnostic code for the disconnected sensor.Expected Result:An open circuit diagnostic code is now active for the disconnected sensor.Results:
OK - A short circuit diagnostic code was active before disconnecting the sensor. An open circuit diagnostic code became active after disconnecting the sensor.Repair: Temporarily connect a new sensor.Check for active diagnostic codes.If the new sensor fixes the problem, reconnect the suspect sensor.If the problem returns, permanently install the new sensor.Verify that the repair eliminates the problem.STOP
Not OK - There is a short circuit between the sensor and the ECM.Repair: Leave the suspect sensor disconnected. Proceed to Test Step 5.Test Step 5. Create an Open Circuit at the ECM
Turn the keyswitch to the OFF position.
Remove the signal wire of the suspect sensor from the appropriate ECM connector.
Turn the keyswitch to the ON position.
Check for active diagnostic codes.Expected Result:An open circuit diagnostic code became active after removing the signal wire.Results:
OK - A short circuit diagnostic code was active before removing the signal wire. An open circuit diagnostic code became active after removing the signal wire. Proceed to Test Step 6.
Not OK - There is still a short circuit diagnostic code.Repair: Connect a test ECM.If the test ECM fixes the problem, reconnect the suspect ECM.If the problem returns, permanently replace the suspect ECM.Verify that the repair eliminates the problem.STOPTest Step 6. Check the Resistance of the Harness
Turn the keyswitch to the OFF position.
Verify that the suspect sensor is disconnected.
Measure the resistance between terminal B (Common) and terminal C (Signal) of the connector for the suspect sensor on the engine harness.Expected Result:The resistance is greater than 20,000 Ohms, or "OL" is displayed on the multimeter.Results:
OK - The resistance is greater than 20,000 Ohms, or "OL" is displayed on the multimeter.Repair: Check the signal wire for a short to ground.Repair the faulty wiring or replace the faulty wiring.Verify that the repair eliminates the problem.STOP
Not OK - There is a short between the pressure sensor common and the signal wire.Repair: Locate the short between the pressure sensor common and the signal wire.Repair the faulty wiring or replace the faulty wiring.Verify that the repair eliminates the problem.STOPTest Step 7. Measure the Sensor Supply Voltage
Turn the key switch to the OFF position.
Disconnect the suspect sensor.
Turn the keyswitch to the ON position.
Measure the voltage from terminal A (+5V) to terminal B (Common).Expected Result:The voltage is 5.0 0.16 VDC.Results:
OK - The sensor supply voltage is correct.Repair: Leave the sensor disconnected. Proceed to Test Step 8.
Not OK - The sensor supply voltage is out of the range.Repair: Check the 5 volt supply wire for an open circuit.Repair the faulty wiring or replace the faulty wiring.Verify that the repair eliminates the problem.STOPTest Step 8. Create a Short Circuit at the