3516B Engine for Caterpillar Built Machines Caterpillar

The Electronic Control Module (ECM) has the ability to automatically lubricate the engine before cranking. This may increase the life of certain engine parts by lubricating the parts before the starting motor is engaged.

The prelubrication system is activated when the keyswitch is turned to the START position. The system prevents the starting motor from engaging while the pump builds pressure in the engine oil system. When adequate pressure is established, the pump shuts off. After a short pause, the starting motor is allowed to engage. The keyswitch must be left in the START position for the duration of the prelube cycle in order to start the engine.

The prelubrication system will not activate if the engine is warm or if the engine has recently shut down.

Illustration 1	g00919872

Test Step 1. Check for Connector Damage.

1. Turn the battery disconnect switch to the OFF position.

2. Turn the keyswitch to the OFF position.

3. Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details.

4. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.

5. Check the ECM connector (allen head screw) for the proper torque of 6.0 N·m (55 lb in).

6. Check the customer connector (allen head screw) for the proper torque of 2.25 ± 0.25 N·m (20 ± 2 lb in).

7. Check the harness and the wiring for abrasion and for pinch points.

Expected Result:

The connectors and wiring should be free of the following problems: damage, corrosion, abrasion and incorrect attachment.

Results:

• OK - The connectors and wiring are okay. Proceed to test step 2.

• Not OK - The connectors and/or wiring need repair.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring.

  Stop.

Test Step 2. Check the ECM Supply Voltage.

1. Turn the battery disconnect switch to the ON position.

2. Turn the keyswitch to the ON position. The engine should be off.

3. Measure the voltage at the ECM connector between P1-4 and P1-11.

Expected Result:

The voltage should be 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC. The voltage is correct. Proceed to test step 3.

• Not OK - The voltage is not 24 ± 3 VDC. The voltage is incorrect.

  Repair: Perform the diagnostic functional test Troubleshooting, "Electrical Power Supply".

  Stop.

Test Step 3. Check for Voltage at the Prelubrication Motor.

1. Turn the keyswitch to the OFF position.

2. Connect the Caterpillar Electronic Technician (ET) to the cab service tool connector J42. Start the Cat ET.

3. Connect a voltmeter between the positive terminal of the prelubrication motor and ground.

4. Turn the keyswitch to the ON position. The engine should be off.

5. Access the override for the prelubrication system.

6. Enable the override for the prelubrication system.

7. Measure the voltage between the positive terminal of the prelubrication motor and ground.

Expected Result:

The voltage should be 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC. Proceed to test step 4.

• Not OK - The voltage is not 24 ± 3 VDC. Proceed to test step 5.

Test Step 4. Check the Operation of the Prelubrication Motor.

1. Turn the keyswitch to the OFF position.

2. Connect one side of a suitable piece of 10 AWG wire to the + Battery terminal.

3. For one second, connect the other end of the wire to the positive terminal of the prelubrication motor.

Expected Result:

The prelubrication motor should start while the wire is connected to the positive terminal of the prelubrication motor.

Results:

• OK - The prelubrication motor starts. There is a problem in the wiring harness at the prelubrication motor.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring.

  Stop.

• Not OK - The prelubrication motor did not start.

  Repair: The problem appears to be in the prelubrication motor. Install a new prelubrication motor. If the condition is no longer present, reinstall the old prelubrication motor. If the original condition returns, replace the prelubrication motor.

  Stop.

Test Step 5. Check the Output Voltage from the Primary Prelube Relay.

1. Connect a voltmeter between wire 337-WH on terminal 30 of the primary prelube relay and ground.

2. Turn the keyswitch to the ON position. The engine should be off.

3. Access the override for the prelubrication system.

4. Enable the override for the prelubrication system.

5. Measure the voltage between wire 337-WH on terminal 30 of the primary prelube relay and ground.

Expected Result:

The voltage should be 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC. Proceed to test step 6.

• Not OK - The voltage is not 24 ± 3 VDC. Proceed to test step 7.

Test Step 6. Check the Voltage to the Coil of the Prelubrication Relay.

1. Connect a voltmeter between wire 337-WH on the prelubrication relay and ground.

2. Turn the keyswitch to the ON position. The engine should be off.

3. Access the override for the prelubrication system.

4. Enable the override for the prelubrication system.

5. Measure the voltage between wire 337-WH on the prelubrication relay and ground.

Expected Result:

The voltage should be 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC.

  Repair: Verify continuity of wire 200-BK between the prelubrication relay and ground. If the wire 200-BK is okay, verify that battery voltage is available to the normally open contacts of the prelubrication relay. If system voltage is available, replace the prelubrication relay.

  Stop.

• Not OK - The voltage is not 24 ± 3 VDC. There is a problem in the wiring harness between the prelubrication relay and the primary prelube relay.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring.

  Stop.

Test Step 7. Check the Voltage to the Coil of the Primary Prelube Relay.

1. Connect a voltmeter between wire F709-BU on terminal 86 of the primary prelube relay and ground.

2. Turn the keyswitch to the ON position. The engine should be off.

3. Access the override for the prelubrication system.

4. Enable the override for the prelubrication system.

5. Measure the voltage between wire F709-BU on terminal 86 of the primary prelube relay and ground.

Expected Result:

The voltage should be 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC. Proceed to test step 8.

• Not OK - The voltage is not 24 ± 3 VDC. Proceed to test step 9.

Test Step 8. Check the Voltage to the Contacts of the Primary Prelube Relay.

1. Connect a voltmeter between wire 150-RD on terminal 87 of the primary prelube relay and ground.

2. Turn the keyswitch to the ON position. The engine should be off.

3. Measure the voltage between wire 150-RD on terminal 87 of the primary prelube relay and ground.

Expected Result:

The voltage should be 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC.

  Repair: Verify continuity of wire 200-BK on terminal 85 between the primary prelube relay and ground. If the wire 200-BK is okay, install a new primary prelube relay. Verify that the prelubrication system is operating correctly.

  Stop.

• Not OK - The voltage is not 24 ± 3 VDC. There is a problem with the wiring harness between the primary prelube relay and the battery.

  Repair: Verify that the circuit breaker for the ECM is not tripped. Repair the connectors or wiring and/or replace the connectors or wiring.

  Stop.

Test Step 9. Check the Voltage at the ECM.

1. Turn the keyswitch to the OFF position.

2. Disconnect ECM connector J1/P1.

3. Remove the wire F709-BU from the ECM connector P1-34.

4. Install a jumper wire with suitable ends into P1-34.

5. Reconnect the ECM connector J1/P1.

6. Turn the keyswitch to the ON position. The engine should be off.

7. Access the override for the prelubrication system.

8. Enable the override for the prelubrication system.

9. Measure the voltage between the wire jumper in P1-34 and ground.

10. Turn the keyswitch to the OFF position.

11. Remove all jumpers and replace all wires.

Expected Result:

The voltage should be 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC. There is an open circuit or excessive resistance in the wiring harness between the ECM and the prelubrication relay.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring.

  Stop.

• Not OK - The voltage was less than 24 ± 3 VDC.

  Repair: Replace the ECM. Refer to the diagnostic procedure Troubleshooting, "Replacing the ECM".

  Stop.