861783 Mercruiser HOSE, Cooler Bypass

Illustration 1 g01007250
Low oil pressure map ( 3176C and 3196) 3406E and 3456 EnginesThe Electronic Control Module (ECM) detects all of the following conditions:
Engine oil pressure is in the "Low Oil Pressure Region" in Illustration 2 for two seconds.
The engine has been running for at least ten seconds.
Illustration 2 g01007252
Low oil pressure map ( 3406E and 3456)System Response:The ECM will log the warning. The ECM will transmit a warning to the display in the cab. The ECM will reset the warning when the oil pressure rises 70 kPa (10 psi) above the low pressure trip line for 20 seconds.
None
There may be a problem with the engine lubrication system.
There may be a problem with the engine oil pressure sensor.Test Step 1. Check the Engine Oil Level
Check the engine oil level.Expected Result:The engine oil level is OK.Results:
OK - The engine oil level is OK. Proceed to Test Step 2.
Not OK - The engine oil level is low.Repair: Add engine oil to the proper level.STOPTest Step 2. Verify Proper Sensor Installation
Check the installation of the engine oil pressure sensor.
Check the wiring of the engine oil pressure sensor. Refer to the Electrical Schematic for the proper wiring. Ensure that all of the wires and connectors are properly connected.Expected Result:The sensor is properly installed and the wiring is correct.Results:
OK - The sensor is properly installed. Proceed to Test Step 3.
Not OK - The sensor is not installed properly.Repair: Install the engine oil pressure sensor properly. Repair the wiring and/or the connectors to the sensor.Verify that the repair eliminates the problem.STOPTest Step 3. Check for Active Diagnostic Codes
Connect the Caterpillar Electronic Technician (Cat ET) to the service tool connector.
Check for active diagnostic codes that are related to the atmospheric pressure sensor and/or to the turbocharger outlet pressure sensor.Expected Result:There are no diagnostic codes that are related to the atmospheric pressure sensor and/or to the turbocharger outlet pressure sensor.Results:
OK - There are no diagnostic codes. Proceed to Test Step 4.
Not OK - There is a diagnostic code that is related to the atmospheric pressure sensor and/or to the turbocharger outlet pressure sensor.Repair: Troubleshoot the diagnostic code before continuing with this procedure.STOPTest Step 4. Check the Status Screen
Turn the keyswitch to the ON position. The engine should be off.
Monitor the status for "Boost Pressure" and "Engine Oil Pressure" on Cat ET.Expected Result:"Boost Pressure" and "Engine Oil Pressure" are less than 10 kPa (2 psi).Results:
OK - The boost pressure and the engine oil pressure are less than 10 kPa (2 psi). Proceed to Test Step 6.
Not OK - Boost Pressure - The boost pressure is greater than 10 kPa (2 psi). Proceed to Test Step 8.
Not OK - Engine Oil Pressure - The engine oil pressure is greater than 10 kPa (2 psi). Proceed to Test Step 9.
Not OK - Both - The boost pressure and engine oil pressure are greater than 10 kPa (2 psi). Proceed to Test Step 5.Test Step 5. Check the Supply Voltage to the Pressure Sensors
Disconnect the atmospheric pressure sensor, the engine oil pressure sensor, and the turbocharger outlet pressure sensor.
Turn the keyswitch to the ON position.
Measure the voltage between terminal A (+5V) and terminal B (Common) of each pressure sensor connector on the engine harness.Expected Result:The voltage is 5.0 0.16 VDC.Results:
OK - The voltage is within the range.Repair: Reconnect the engine oil pressure sensor and the turbocharger outlet pressure sensor.Temporarily connect a new atmospheric pressure sensor.If the new sensor fixes the problem, reconnect the suspect sensor.If the problem returns, permanently replace the sensor.Verify that the repair eliminates the problem.STOP
Not OK - There is a problem