C32 Marine Auxiliary Engines Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with a prelubrication system or if one of the diagnostic codes in Table 1 is active or easily repeated.

When the ECM receives a request for starting the engine the ECM has the ability to automatically lubricate the engine before the engine is cranked. The ECM controls a motor that drives a prelubrication oil pump. This motor will drive the pump until one of the following conditions are met:

• The engine oil pressure reaches the desired level for the prelubrication.

• The time that is programmed for the configuration parameter "Prelube Duration" has elapsed.

• The operator activates the prelube override switch.

Note: If the configuration parameter "Prelube Duration" is set to zero seconds, the ECM will skip the process of prelubrication. The ECM will begin cranking the engine immediately. Refer to Troubleshooting, "Configuration Parameters" for the available range and default setting of this parameter.

An override for the prelubrication system is available in Caterpillar Electronic Technician (ET). The override allows the technician to activate the prelubrication system for service and testing. The test is functional only when the engine speed is zero rpm. The test is accessed by selecting the following menus on Cat ET:

• "Diagnostics"

• "Diagnostic Tests"

• "Override Parameters"

Illustration 1	g01408611
Schematic for the prelubrication system

Test Step 1. Inspect the Electrical Connectors and the Wiring

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Illustration 2	g01409094
Location of the connectors for the engine prelube system (rear engine view) (1) J1/P1 ECM connectors (2) Customer connector

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Illustration 3	g01409254
Location of the connectors and component for the engine prelube system inside the engine mounted control panel (3) Connector for the engine mounted control panel (4) Mating connector for the prelube relay (5) Prelube override switch

1. Remove the electrical power from the ECM.

2. Thoroughly inspect the connectors (1), (2), (3) and (4) .

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Illustration 4	g01409300
Terminal locations at the P1 ECM connector for the prelubrication system (P1-11) Prelubrication relay (P1-54) Prelube override switch (P1-61) Battery −

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Illustration 5	g01409354
Terminal locations at the connector for the engine mounted control panel (Terminal 2) Battery − (Terminal 21) Prelubrication relay (Terminal 37) Prelube override switch

3. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors and the other connections that are associated with the circuit.

4. Check the allen head screw for each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect " for details.

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

Expected Result:

All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points.

Results:

• OK - The connectors and wiring appear to be OK. Proceed to Test Step 2.

• Not OK - There is a problem in the connectors and/or wiring.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.

  STOP

Test Step 2. Check for Active Diagnostic Codes

1. Connect Cat ET to the service tool connector.

2. Restore the electrical power to the ECM.

3. Select diagnostic tests from Cat ET.

4. Select the "Override Parameters" screen on Cat ET.

5. Activate the override for the prelubrication system.

6. Monitor the active diagnostic code screen on Cat ET. Check the prelubrication system for an active diagnostic code.

   Note: Wait at least 30 seconds in order for the diagnostic code to become active.

7. Disable the override for the prelubrication system.

Expected Result:

No diagnostic codes are active.

Results:

• OK - No diagnostic codes are active, but a problem is suspected in the prelubrication system. Proceed to Test Step 6.

• Active -6 Code - A -6 diagnostic code is active at this time. A short is detected in the circuit for the prelubrication relay. Proceed to Test Step 3.

• Active -5 Code - A -5 diagnostic code is active at this time. An open is detected in the circuit for the prelubrication relay. Proceed to Test Step 4.

Test Step 3. Create an Open Circuit at the Prelubrication Relay

1. Remove the electrical power from the ECM.

2. Disconnect the connector for the prelubrication relay.

3. Restore the electrical power to the ECM.

4. Select diagnostic tests from Cat ET.

5. Select the "Override Parameters" screen on Cat ET.

6. Activate the override for the prelubrication system.

7. Monitor the active diagnostic code screen on Cat ET. Check the prelubrication system for an active diagnostic code.

   Note: Wait at least 30 seconds in order for the diagnostic code to become active.

8. Remove the electrical power from the ECM.

Expected Result:

A -6 diagnostic code was active for the prelubrication relay. After creating an open at the prelubrication relay, a -5 diagnostic code is now active.

Results:

• OK - A -6 diagnostic code was active before disconnecting the wire. A -5 diagnostic code became active after disconnecting the wire.

  Repair: The harness and the ECM are OK. The short circuit is in the prelubrication relay. Perform the following repair:

  1. Temporarily connect a new prelubrication relay.

  2. Recheck the circuit in order to ensure that the original problem is resolved with the installation of the new relay.

  3. If the problem is resolved with the new relay, reconnect the suspect relay. If the problem returns with the suspect relay, permanently install the new relay.
  Clear any logged diagnostic codes.

  STOP

• Not OK - A -6 diagnostic code remains active. There is a short between the prelubrication relay and the ECM. There may be a problem with the ECM. Proceed to Test Step 5.

Test Step 4. Create a Short at the Connector for the Prelubrication Relay

1. Remove the electrical power from the ECM.

2. Fabricate a jumper wire that is long enough to create a short circuit between the terminals of the harness connector for the prelubrication relay. Crimp connector pins to each end of the jumper wire.

3. Install the jumper wire between the terminals of the harness connector at the prelubrication relay.

4. Restore the electrical power to the ECM.

5. Select diagnostic tests from Cat ET.

6. Select the "Override Parameters" screen on Cat ET.

7. Activate the override for the prelubrication system.

8. Monitor the active diagnostic code screen on Cat ET. Check the prelubrication system for an active diagnostic code.

   Note: Wait at least 30 seconds in order for the diagnostic code to become active.

9. Disable the override for the prelubrication system.

10. Remove the electrical power from the ECM.

11. Restore the wiring to the original configuration.

Expected Result:

A -6 diagnostic code is active when the jumper wire is installed. A -5 diagnostic code is active when the jumper wire is removed.

Results:

• OK - A -6 diagnostic code is active when the jumper wire is installed. A -5 diagnostic code is active when the jumper wire is removed.

  Repair: The engine harness and the ECM are OK. The open circuit is in the coil of the prelubrication relay. Perform the following repair:

  1. Temporarily connect a new prelubrication relay.

  2. Recheck the circuit in order to ensure that the original problem is resolved with the installation of the new relay.

  3. If the problem is resolved with the new relay, reinstall the suspect relay. If the problem returns with the installation of the suspect relay, permanently install the new relay.
  Clear any logged diagnostic codes.

  STOP

• Not OK - The -5 diagnostic code remains active with the jumper in place. The open circuit is between the ECM and the connector for the prelubrication relay. There may be a problem with the ECM. Proceed to Test Step 5.

Test Step 5. Test for the Proper Operation of the ECM

1. Remove the electrical power from the ECM.

2. Fabricate two jumper wires that are long enough to create a test circuit at the ECM connector. Crimp a connector socket to one end of each of the jumper wires.

3. Disconnect the J1/P1 ECM connector.

4. Remove the wires from terminal locations P1-11 and P1-61 at the ECM connectors. Install one of the jumper wires into each of these terminal locations.

5. Connect the ECM connectors.

6. Check the Operation of the ECM by Creating an Open Circuit at the ECM Connector:

   1. Hold the loose ends of each of the jumper wires away from any ground source in order to create an open circuit condition.

   2. Restore the electrical power to the ECM.

   3. Monitor the active diagnostic code screen on Cat ET. Check the prelubrication system for an active -5 diagnostic code.

      Note: Wait at least 30 seconds in order for the diagnostic code to become active.

   4. Select diagnostic tests from Cat ET.

   5. Select the "Override Parameters" screen on Cat ET.

   6. Activate the override for the prelubrication system.

   7. Disable the override for the prelubrication system.

7. Check the Operation of the ECM by Creating a Short Circuit at the ECM Connector:

   1. Short circuit the loose ends of the jumper wires that are for the prelubrication relay.

   2. Restore the electrical power to the ECM.

   3. Monitor the active diagnostic code screen on Cat ET. Check the prelubrication system for an active diagnostic code.

      Note: Wait at least 30 seconds in order for the diagnostic codes to become active.

   4. Select diagnostic tests from Cat ET.

   5. Select the "Override Parameters" screen on Cat ET.

   6. Activate the override for the prelubrication system.

   7. Disable the override for the prelubrication system.

8. Remove the electrical power from the ECM.

9. Restore the wiring to the original configuration.

Expected Result:

A -5 diagnostic code is active when the loose ends of the wires for the prelubrication relay are open at the ECM connector. A -6 diagnostic code is active when the loose ends of the wires for the prelubrication relay are shorted at the ECM connector.

Results:

• OK - A -5 diagnostic code is active when the wires are open at the ECM connector. A -6 diagnostic code is active when the wires are shorted at the ECM connector.

  Repair: The ECM is operating properly. The problem is in the wiring between the ECM and the prelubrication relay. Repair the connectors or wiring and/or replace the connectors or wiring. Verify that the original problem has been resolved.

  STOP

• Not OK - One of the following conditions exists: The -5 diagnostic code is not active when the loose ends of the wires for the prelubrication relay are open at the ECM connector. The -6 diagnostic code is not active when the loose ends of the wires for the prelubrication relay are shorted at the ECM connector.

  Repair: Replace the ECM. Refer to Troubleshooting, "ECM - Replace". Verify that the problem is resolved.

  STOP

Test Step 6. Check the Voltage to the Secondary Circuit of the Prelubrication Relay

1. Disconnect the wire that is between the prelubrication relay and the prelubrication motor from the terminal bolt at the prelubrication relay.

2. Connect a voltmeter between the terminal bolt of the relay and the engine ground stud.

3. Restore the electrical power to the ECM.

4. Proceed to the "Diagnostic Overrides" screen on Cat ET.

5. Activate the override for the prelubrication system.

6. Measure the voltage at the terminal bolt.

7. Remove the electrical power from the ECM.

8. Restore the wiring to the original configuration.

Expected Result:

The voltage measures 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC. The prelubrication relay is operating properly. Proceed to Test Step 7.

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

  Repair: Perform the following steps.

  1. Remove the wire that is between the prelubrication relay and the circuit breaker from the terminal bolt at the prelubrication relay. Measure the voltage between the loose end of the wire and the engine ground stud.

     If 24 ± 3 VDC is present on the loose end of the wire, there is a problem with the prelubrication relay. Replace the relay. Verify that the problem has been resolved.

     If 24 ± 3 VDC is not present at the loose end of the wire, there is a problem with the circuit between the batteries and the relay. Check that the circuit breaker has not been tripped. Also, check that the batteries are fully charged. If the circuit breaker has not been tripped and if the circuit breaker and the batteries are in good repair, there is a problem in the harness wiring. Repair the wiring or replace the wiring that is between the batteries and the prelubrication relay.

  STOP

Test Step 7. Check the Voltage at the Prelubrication Motor

1. Disconnect the wire that is between the prelubrication relay and the prelubrication motor from the terminal bolt at the prelubrication motor.

2. Connect a voltmeter between the loose end of the wire and the engine ground stud.

3. Restore the electrical power to the ECM.

4. Proceed to the "Diagnostic Overrides" screen on Cat ET.

5. Use Cat ET in order to activate the override for the prelubrication system.

6. Measure the voltage between the loose end of the wire and the engine ground.

7. Remove the electrical power from the ECM.

Expected Result:

The voltage is 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC. The circuit for the prelubrication system is OK. Proceed to Test Step 8.

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

  Repair: Voltage is present at the relay, but voltage is not present at the motor. There is a problem with the wiring that is between the prelubrication relay and the prelubrication motor. Repair the wiring or replace the wiring. Verify that the original problem has been resolved.

  STOP

Test Step 8. Check the Operation of the Prelubrication Motor

1. Remove the electrical power from the ECM.

2. Fabricate a jumper wire out of 10 AWG wire that can be used to provide a test circuit between the battery and the prelubrication motor. Connect one side of the jumper 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 starts 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: Verify that the ground circuit at the prelubrication motor has continuity to engine ground. If the ground circuit is OK, the problem is in the prelubrication motor. Install a new prelubrication motor. Verify that the original problem has been resolved.

  STOP