MOUNTING PLT 1618391 - Caterpillar

Test Step 6.
Not OK - The resistance is not between 250 Ohms and 500 Ohms. The relay is faulty.Repair: Replace the relay.Verify that the repair eliminates the problem.STOPTest Step 6. Check the Signal Voltage to the Prelubrication Relay
Restore electrical power to the ECM. The engine should not be running.
Proceed to the "Diagnostic Override Screen" in Cat ET.
Activate the prelubrication system.
Measure the voltage between the terminal (signal voltage) of the prelubrication relay and chassis ground.Expected Result:The voltage is 24.0 8.0 VDC.Results:
OK - The signal voltage is 24.0 8.0 VDC. Proceed to Test Step 10.
Not OK - The signal voltage is not 24.0 8.0 VDC. Proceed to Test Step 7.Test Step 7. Check the Ground Circuit for the Prelubrication Relay
Remove electrical power from the ECM.
Measure the resistance between terminal 86 of the prelubrication relay and chassis ground.Expected Result:The resistance does not indicate an open circuit.Results:
OK - The resistance does not indicate an open circuit. Proceed to Test Step 8.
Not OK - The resistance indicates an open circuit. The ground for the relay for the prelubrication pump is faulty.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 8. Check the Harness to the ECM
Verify that the electrical power is removed from the ECM.
Disconnect the J1/P1 ECM connector.
Remove the wire from terminal P1-34 (prelubrication relay signal).
Reconnect the J1/P1 ECM connector.
Disconnect the connector for the prelubrication relay.
Use a suitable piece of wire to short terminal 85 (signal voltage ) and terminal 86 (return) on the connector for the prelubrication relay.
Measure the resistance between the end of the wire from terminal P1-34 (prelubrication relay signal) and chassis ground.Expected Result:The resistance does not indicate an open circuit.Results:
OK - The resistance does not indicate an open circuit. Proceed to Test Step 9.
Not OK - There is an open circuit in the wiring harness between the prelubrication relay and the ECM.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 9. Check the ECM
Verify that the electrical power is removed from the ECM.
Disconnect the J1/P1 ECM connector.
Install a jumper wire into terminal P1-34 (prelubrication relay signal).
Reconnect the J1/P1 ECM connector.
Return the wiring at the prelubrication relay to the original configuration.
Restore electrical power to the ECM. The engine should not be running.
Measure the voltage between the jumper wire from terminal P1-34 (prelubrication relay signal) and chassis ground.
Remove electrical power from the ECM.
Restore the wiring to the original configuration.Expected Result:The supply voltage is 24.0 8.0 VDC.Results:
OK