0439374 JOHNSON CARBURETOR ASSEMBLY

Illustration 1 g01007408
High fuel pressure mapSystem 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 fuel pressure drops 10 kPa (1.5 psi) below the high pressure trip line for five seconds.
There may be a problem with the fuel system.
There may be a problem with the fuel pressure sensor.Test Step 1. Verify Proper Sensor Installation
Check the installation of the fuel pressure sensor.
Check the wiring of the fuel 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 2.
Not OK - The sensor is not installed properly.Repair: Install the fuel pressure sensor properly. Repair the wiring and/or the connectors to the sensor.Verify that the repair eliminates the problem.STOPTest Step 2. 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 3.
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 3. Check the Status Screen
Turn the keyswitch to the ON position. The engine should be off.
Monitor the status for "Boost Pressure" and "Fuel Pressure" on Cat ET.Expected Result:"Boost Pressure" and "Fuel Pressure" are less than 10 kPa (2 psi).Results:
OK - The boost pressure and the fuel pressure are less than 10 kPa (2 psi). Proceed to Test Step 5.
Not OK - Boost Pressure - The boost pressure is greater than 10 kPa (2 psi). Proceed to Test Step 7.
Not OK - Fuel Pressure - The fuel pressure is greater than 10 kPa (2 psi). Proceed to Test Step 8.
Not OK - Both - The boost pressure and fuel pressure are greater than 10 kPa (2 psi). Proceed to Test Step 4.Test Step 4. Check the Supply Voltage to the Pressure Sensors
Disconnect the atmospheric pressure sensor, the fuel 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 fuel pressure sensor and the turbocharger outlet pressure sensor.Temporarily