0438557 JOHNSON FUEL PUMP ASSY., Lower

Illustration 1 g00674105
Test Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF/RESET position.
Thoroughly inspect the J1/P1 ECM connector, the J2/P2 ECM connector, the J3/P3 machine connector, and all other connectors in the wiring harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Inspect the following components for damage, corrosion, and incorrect attachment:
Battery posts
Alternator
Breaker
Engine ground
Chassis groundExpected Result:All connectors, pins, and sockets are completely inserted and coupled. The harness and wiring are free of corrosion, of abrasions, and of pinch points. All connections and grounds are tight and free of corrosion.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 2. Verify Operation of the Prelubrication Oil Pump
Turn the keyswitch to the ON position. The engine should be OFF.
Proceed to the "Diagnostic Override Screen" in Cat ET.
Activate the prelubrication system.Expected Result:The prelubrication oil pump activates.Results:
OK - The prelubrication system is functioning properly.STOP
Not OK - Proceed to Test Step 3.Test Step 3. Check the Resistance of the Prelubrication Relay
Turn the keyswitch to the OFF/RESET position.
Use a multimeter to measure the resistance across the terminal for the signal input of the prelubrication relay and the ground terminal of the prelubrication relay.Expected Result:The resistance is between 250 Ohms and 500 Ohms.Results:
OK - Proceed to Test Step 4.
Not OK - The relay is faulty.Repair: Replace the relay.Verify that the repair eliminates the problem.STOPTest Step 4. Check the Supply Voltage to the Prelubrication Oil Pump
Turn the keyswitch to the ON position. The engine is OFF.
Proceed to the "Diagnostic Override Screen" in Cat ET.
Activate the prelubrication system.
Use a multimeter to measure the voltage between the terminal for power supply on the prelubrication oil pump and chassis ground when the prelubrication system is activated.Expected Result:The supply voltage is 24.0 8.0 VDC.Results:
OK - Proceed to Test Step 5.
Not OK - The prelubrication oil pump is not receiving the correct signal. Proceed to Test Step 6.Test Step 5. Check the Ground to the Prelubrication Oil Pump
Use a multimeter to check for continuity between the negative terminal of the prelubrication oil pump and chassis ground.Expected Result:The resistance is less than 10 Ohms.Results:
OK - The prelubrication oil pump is faulty.Repair: Replace the prelubrication oil pump.Verify that the repair eliminates the problem.STOP
Not OK - The ground for the prelubrication oil pump is faulty.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 6. Check the Power Supply to the Prelubrication Relay
Use a multimeter to measure the voltage from the terminal for the power supply to the prelubrication relay to chassis ground.Expected Result:The supply voltage is 24.0 8.0 VDC.Results:
OK - Proceed to Test Step 7.
Not OK - There is a problem in the wiring between the prelubrication relay and the +Battery.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 7. Check the Output Voltage of the Prelubrication Relay
Turn the keyswitch to the ON position. The engine is OFF.
Proceed to the "Diagnostic Override Screen" in Cat ET.
Activate the prelubrication system.
Use a multimeter to measure the voltage between the terminal for the power output of the prelubrication relay and chassis ground when the prelubrication system is activated.Expected Result:The output voltage is 24.0 8.0 VDC.Results:
OK - There is a problem in the wiring between the prelubrication relay and the pump.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOP
Not OK - Proceed to Test Step 8.Test Step 8. Check the Signal to the Prelubrication Relay
Turn the keyswitch to the ON position. The engine is OFF.
Proceed to the "Diagnostic Override Screen" in Cat ET.
Activate the prelubrication system.
Use a multimeter to measure the voltage across the terminal for the signal input of the prelubrication relay and the ground terminal of the prelubrication relay when the prelubrication system is activated.Expected Result:The output voltage is 24.0 8.0 VDC.Results:
OK - The prelubrication relay is faulty.Repair: Replace the prelubrication relay.Verify that the repair eliminates the problem.STOP
Not OK - Proceed to Test Step 9.Test Step 9. Check the Ground for the Prelubrication Relay
Use a multimeter to check the resistance between the ground terminal of the prelubrication relay and chassis ground.Expected Result:The resistance is less than 10 Ohms.Results:
OK - Proceed to Test Step 10.
Not OK - The ground for the prelubrication relay is faulty.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 10. Check the Power Supply to the Prelubrication Relay
Illustration 2 g00674678
Connector for the prelubrication relay
Use a multimeter to measure the voltage across terminal 30 (+Battery) and chassis ground.Expected Result:The voltage is 24.0 8.0 VDC.Results:
OK - Proceed to Test Step 11.
Not OK - There is a problem in the wiring between the prelubrication relay and the +Battery.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 11. Check the Output Voltage of the Prelubrication Relay
Illustration 3 g00674678
Connector for the prelubrication relay
Ensure that all connectors are connected to the wiring harness.
Turn the keyswitch to the ON position. The engine is OFF.
Proceed to the "Diagnostic Override Screen" in Cat ET.
Activate the prelubrication system.