3500B Marine Engines Caterpillar

The engine has two Electronic Control Modules (ECM). The secondary ECM controls power to the backup Engine Speed/Timing sensor. The secondary ECM also controls the air shutoff relay. All other engine functions are controlled by the primary ECM.

When power is applied to the system, the secondary ECM will illuminate the Ready Lamp for 5 seconds. When the secondary ECM assumes engine control, the Active Lamp will illuminate.

Note: Refer to the diagnostic functional test Troubleshooting, "ECM/Personality Module".

The primary ECM controls the engine:

• Engine speed

• Governing

• Engine monitoring

The secondary ECM will take control due to the following reasons:

• Loss of the primary ECM heartbeat signal

• Two injector faults for the 12 cylinder engine

• Four injector faults for the 16 cylinder engine

The primary ECM also communicates some information to the display.

The secondary ECM provides governing if the primary ECM fails. If this occurs, the secondary ECM automatically assumes engine control.

Note: The secondary ECM is not a fully functional ECM. The secondary ECM is used to keep the engine running until the vessel can obtain proper service. The secondary ECM is used to control the governing of the engine.

Illustration 1	g00981150

Test Step 1. Check for Connector Damage.

1. Turn the ECS to the OFF/RESET position.

2. Disconnect the main power.

3. Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all 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 2.25 ± 0.25 N·m (20 ± 2 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:

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

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 Active Lamp and the Ready Lamp for the secondary ECM.

1. Observe the Active lamp and the Ready lamp on the instrument panel when the ECS is turned to the STOP position.

Expected Result:

Both lamps should illuminate for five seconds. The Ready Lamp should remain illuminated. The Active lamp should illuminate for five seconds. The Active lamp should then turn off.

Results:

• OK - Both lamps illuminated for five seconds. The Ready Lamp remained illuminated. The Active Lamp is off. The problem is no longer present.

  Repair: The secondary ECM reads the primary ECM heartbeat signal. Active injector codes are not present. If the problem is intermittent, perform the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".

  STOP

• Not OK - The ready lamp is not illuminated. Proceed to Test Step 4.

• ACTIVE LAMP ON - Both lamps illuminated for five seconds. The Active lamp remained illuminated. The secondary ECM has assumed control of the engine. Proceed to Test Step 3.

Test Step 3. Check for LOGGED Diagnostic Codes.

1. Turn the ECS to the OFF/RESET position.

2. Connect the Caterpillar Electronic Technician (ET).

3. Turn the ECS to the STOP position.

4. Observe the diagnostic codes on the Cat ET.

   Note: The secondary ECM will assume control of a 12 cylinder engine if two or more diagnostic codes for the injectors are present. The secondary ECM will assume control of a 16 cylinder engine if four or more diagnostic codes for the injectors are present.

Expected Result:

LOGGED diagnostic codes are present.

Results:

• OK - A diagnostic code of CID 0579 - FMI 05 or a diagnostic code of CID 0579 - FMI 06 is present. Proceed to Test Step 8.

• OK - An error code for the fuel injectors is present.

  Repair: Perform the diagnostic functional test Troubleshooting, "Injector Solenoids".

  STOP

• Not OK - No LOGGED diagnostic codes are present. Proceed to Test Step 4.

Test Step 4. Check the Primary ECM Heartbeat Signal at the Primary ECM.

1. Turn the ECS to the OFF/RESET position.

2. Disconnect the primary ECM connector J1/P1.

3. Remove wire C401-BU(Blue)from the primary ECM connector P1-22. Install a wire jumper with sockets on both ends into primary ECM connector P1-22 and secondary ECM connector P1–12 or 20.

4. Connect a multimeter capable of reading frequency between the wire jumper in P1-22 and the engine ground.

5. Reconnect the primary ECM connector J1/P1.

6. Turn the ECS to the STOP position.

7. Observe the frequency (primary ECM Heartbeat Signal) on the multimeter display. If a number does not appear on the multimeter display, verify the connections. Measure the frequency from another digital sensor. Verify that the multimeter is operating correctly.

   Note: The heartbeat wire needs to be connected to both Primary and Secondary ECMs to measure the frequency.

8. Turn the ECS to the OFF/RESET position.

9. Remove the wire jumper. Reconnect all wires and connectors.

Expected Result:

The frequency should be between 15.67 and 17.67 Hz.

Results:

• OK - The frequency is between 15.67 and 17.67 Hz. Proceed to Test Step 5.

• Not OK - The frequency is not between 15.67 and 17.67 Hz. The primary ECM Heartbeat Signal is not within the frequency range.

  Repair: Verify that the proper software has been installed. Verify that the primary ECM is receiving the correct voltage. Perform the diagnostic functional test Troubleshooting, "Electrical Power Supply".

  STOP

Test Step 5. Check the Primary ECM Heartbeat Signal at the Secondary ECM.

1. Verify that ALL of the connectors are reconnected.

2. Turn the ECS to the OFF/RESET position.

3. Disconnect the secondary ECM connector J1/P1.

4. Remove the wire C401-BU(Blue)from the secondary ECM connector P1-12. Install a wire jumper with sockets on both ends into secondary ECM connector P1-12 and primary ECM connector P1-22.

5. Connect a multimeter capable of reading frequency between wire C401-BU(Blue)and engine ground.

6. Reconnect the secondary ECM connector J1/P1.

7. Turn the ECS to the STOP position.

8. Observe the frequency (primary ECM Heartbeat Signal) on the multimeter display. If a number does not appear on the multimeter display, verify the connections. Measure the frequency from another digital sensor. Verify that the multimeter is operating correctly.

   Note: The heartbeat wire needs to be connected to both Primary and Secondary ECMs to measure the frequency.

9. Remove the wire C401-BU(Blue)from the secondary ECM connector P1-20. Install a wire jumper with sockets on both ends into secondary ECM connector P1-20 and primary ECM connector P1-22.

10. Repeat the above measurement by using the wire C401-BU(Blue)from the secondary ECM connector P1-20.

11. Turn the ECS to the OFF/RESET position.

12. Reconnect all wires and connectors.

Expected Result:

The frequency should be between 15.67 and 17.67 Hz.

Results:

• OK - The frequency is between 15.67 and 17.67 Hz. Proceed to Test Step 6.

• Not OK - The frequency is not between 15.67 and 17.67 Hz. The signal is not within the frequency range. There is a problem in the wiring harness between the primary ECM and the secondary ECM.

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

  STOP

Test Step 6. Test the Ready Lamp.

1. Turn the ECS to the OFF/RESET position.

2. Disconnect the secondary ECM connector J1/P1.

3. Remove the wire 675-BR(Brown)from the secondary ECM connector J1-22.

4. Connect a wire jumper between wire 675-BR(Brown)and the engine ground.

5. Reconnect the secondary ECM connector J1/P1.

6. Turn the ECS to the STOP position.

7. Observe the Ready Lamp.

8. Turn the ECS to the OFF/RESET position.

9. Remove the wire jumper. Reconnect all wires and connectors.

Expected Result:

The lamp should illuminate while the jumper is connected. The lamp should not illuminate when the jumper is removed.

Results:

• OK - The lamp illuminates while the jumper is connected. The lamp does not illuminate when the jumper is removed. Proceed to Test Step 7.

• Not OK - The lamp circuit is not functioning properly.

  Repair: Verify that voltage is present on wire 150-OR(Orange)at one side of the lamp. If voltage is present, replace the lamp. If voltage is not present, troubleshoot the voltage supply to wire 150-OR(Orange).

  STOP

Test Step 7. Test the Active Lamp.

1. Turn the ECS to the OFF position.

2. Disconnect the secondary ECM connector J1/P1.

3. Remove the wire 676-PU(Purple)from the secondary ECM connector J1-21.

4. Connect a wire jumper between wire 676-PU(Purple)and the engine ground.

5. Reconnect the secondary ECM connector J1/P1.

6. Turn the ECS to the STOP position.

7. Observe the Active Lamp.

8. Turn the ECS to the OFF/RESET position.

9. Remove the wire jumper. Reconnect all wires and connectors.

Expected Result:

The lamp should illuminate while the jumper is connected. The lamp should not illuminate when the jumper is removed.

Results:

• OK - The lamp circuit is okay.

  Repair: If the problem is intermittent, perform the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".

  STOP

• Not OK - The lamp circuit is not functioning properly.

  Repair: Verify that voltage is present on wire 150-OR(Orange)at one side of the lamp. If voltage is present, replace the lamp. If voltage is not present, troubleshoot the voltage supply to wire 150-OR(Orange).

  STOP

Test Step 8. Check for Shorts in the Wiring Harness.

1. Turn the ECS to the OFF/RESET position.

2. Disconnect the primary ECM and the secondary ECM connector J1/P1.

3. Measure the resistance at the primary ECM between P1-22 and engine ground.

4. Measure the resistance at the secondary ECM between P1-20 and engine ground.

5. Measure the resistance at the secondary ECM between P1-12 and engine ground.

6. Measure the resistance at the secondary ECM between P1-20 and P1-5.

7. Measure the resistance at the secondary ECM between P1-12 and P1-5.

8. Measure the resistance at the primary ECM between P1-22 and P1-5.

9. Reconnect all wires and connectors.

Expected Result:

The resistance should be greater than 20,000 Ohms.

Results:

• OK - The resistance is greater than 20,000 Ohms. Proceed to Test Step 9.

• Not OK - There is a problem in the wiring harness.

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

  STOP

Test Step 9. Check for Opens in the Wiring Harness.

1. Measure the resistance of the wire C401-BU(Blue)between the secondary ECM P1-20 and the primary ECM P1-22.

2. Measure the resistance of the wire C401-BU(Blue)between the secondary ECM P1-12 and the primary ECM P1-22.

3. Reconnect all wires and connectors.

Expected Result:

The resistance should be less than 5 Ohms.

Results:

• OK - The resistance is less than 5 Ohms. Proceed to Test Step 10.

• Not OK - There is a problem in the wiring harness.

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

  STOP

Test Step 10. Check the Personality Module.

1. Determine if new software has recently been installed.

   Note: If the secondary ECM does not see a primary ECM Heartbeat Signal, the secondary ECM will assume engine control. The power must be reset. After the power has been reset the primary ECM will take control of the engine.

2. Turn the ECS to the OFF/RESET Position.

3. Connect the Cat ET.

4. Wait for 70 seconds.

5. Verify that the correct Personality Module (software) is installed in the primary ECM.

6. Turn the ECS to the STOP position.

Expected Result:

No LOGGED diagnostic codes should be present.

Results:

• OK - No LOGGED diagnostic codes are present.

  Repair: Verify that the Active lamp and the Ready lamp on the instrument panel illuminate when the ECS is turned to the STOP position.

  STOP

• Not - OK - LOGGED diagnostic codes are present.

  Repair: Repair any diagnostic codes that are present.

  STOP