3512B Marine Auxiliary Engine Caterpillar

The Electronic Control Module (ECM) receives electrical power from the Engine Control Switch (ECS) when the Engine Control Switch is in the STOP position, the DGCP ENABLE position, or the BLACK START ENABLE position. A signal is provided to the ECM that senses the position of the Engine Control Switch. When the ECM senses voltage on this input, the ECM will power up. If the voltage is removed from the input, the ECM will power down.

With intermittent faults, you may want to bypass the engine wiring. Bypassing the wiring helps to locate the problem. If the problem is no longer present with the bypass in place, the engine wiring is faulty.

Illustration 1	g00925722

Illustration 2	g00598859

Test Step 1. Check for Connector Damage.

1. Verify that the circuit breakers on the Engine Instrument Panel are not tripped.

2. Turn BATTCB to the OFF position.

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

4. Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Perform the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".

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

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

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

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

Expected Result:

All connectors, pins, and sockets are completely coupled. The harness and wiring should be free of corrosion, abrasion or 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 Voltage to the ECM.

1. Disconnect the Primary ECM connector and the Secondary ECM connector J1/P1.

2. Turn BATTCB to the ON position.

3. Turn the ECS to the STOP position.

   Note: If a remote START/STOP switch is installed, the remote START/STOP switch must be in the COOL/STOP position.

4. Measure the voltage at the Primary ECM and the Secondary ECM. Measure the voltage between P1-6 and P1-5. Measure the voltage between P1-4 and P1-11. Measure the voltage between P1-23 and P1-11.

Expected Result:

The voltage should be 24 ± 3 VDC.

The difference between the three voltage measurements should be less than 0.5 VDC.

Results:

• OK - The ECM is receiving the correct voltage. Proceed to test step 8.

• Not OK - The voltage is incorrect. The wiring or components between the battery and the ECM may be preventing the voltage from reaching the ECM. Proceed to test step 3.

Test Step 3. Check the Black Start System for proper operation.

1. Turn BATTCB to the OFF position.

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

3. Refer to the Black Start System technical manual for information on troubleshooting and repair.

Expected Result:

The power supply voltage is correct.

Results:

• OK - The Black Start System is OK. Proceed to test step 4.

• Not OK - The Black Start System is Not OK.

  Repair: Refer to the Black Start System technical manual for information on troubleshooting and repair.

  Stop.

Test Step 4. Check the Voltage at the Emergency Stop Relay.

1. Reconnect the Primary ECM connector and the Secondary ECM connector J1/P1.

2. Turn BATTCB to the ON position.

3. Turn the ECS to the STOP position.

   Note: If a remote START/STOP switch is installed, the remote START/STOP switch must be in the COOL/STOP position.

4. Measure the voltage from wire 103-RD on terminal 30 of the emergency stop relay to the - Battery terminal.

Expected Result:

The voltage should be 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC. Proceed to test step 5.

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

Test Step 5. Check the Voltage at the ECM Relay.

1. Measure the voltage from wire 103-RD on terminal 86 of the ECM relay to the - Battery terminal.

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.

  Repair: Check the voltage on terminal 87A on the Emergency Stop relay. If the voltage is correct, the wire from the Emergency Stop relay to the ECM relay may be the problem. If the voltage is incorrect, replace the Emergency Stop relay.

  Stop.

Test Step 6. Check the Voltage at the Output of the ECM Relay.

1. Measure the voltage from wire 102-RD on terminal 87 of the Primary ECM relay to the - Battery terminal.

2. Measure the voltage from wire 150-OR on terminal 30 of the Primary ECM relay to the - Battery terminal.

3. Measure the voltage from wire 102-RD on terminal 87 of the Secondary ECM relay to the - Battery terminal.

4. Measure the voltage from wire 106-WH on terminal 30 of the Secondary ECM relay to the - Battery terminal.

Expected Result:

The voltage should be 24 ± 3 VDC on all terminals.

Results:

• OK - The voltage is 24 ± 3 VDC on all terminals.

  Repair: The wire from the ECM relay to the ECM is bad. Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

• Not OK - Terminal 87 - The voltage is incorrect on terminal 87.

  Repair: Verify that the circuit breakers for the battery and for the ECM are not tripped. Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

• Not OK - Terminal 30 - The voltage is incorrect on terminal 30.

  Repair: Verify that wire 200-BK on terminal 85 of the ECM relay is not damaged or open. If wire 200-BK is okay, replace the ECM relay. Verify that the original condition is resolved.

  Stop.

Test Step 7. Check the Voltage at the Engine Control Switch.

1. Measure the voltage at the ECS when the switch is in the positions that are listed in Table 1.
   Show/hide table

   Table 1

   Engine Control Switch
   Switch Position	Terminal	Voltage
   STOP	1, 3, 4, 5, 16, 18, 19, 20	24 ± 3 VDC
   BLACK START ENABLE	1, 3, 4, 5, 16, 18, 19, 20	24 ± 3 VDC
   DGCP ENABLE	1, 3, 4, 5, 16, 18, 19, 20	24 ± 3 VDC (1).
   OFF/RESET	3, 4, 5, 16, 18, 19, 20	0 VDC

   Show/hide table

   ( 1 )

   Check the remote system shutdown device

Expected Result:

The measured voltage at the ECS should agree with the voltage that is listed in Table 1.

Results:

• OK - The correct voltage appears at the ECS.

  Repair: Verify that the emergency stop is working correctly. The problem could be in two places. Check the wiring between the ECS and the emergency stop switch. Check the wiring between the emergency stop switch and the emergency stop relay. Perform the diagnostic functional test Troubleshooting, "Emergency Stop Switch".

  Stop.

• Not OK - Terminal 1 - The correct voltage does not appear on Terminal 1 of the ECS.

  Repair: Check the harness between the ECS and the Black Start System. Verify that BATTCB and CSCB are not tripped. The problem is in the wiring and/or connectors. Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

• Not OK - Other Terminals - The correct voltage appears on terminal 1 on the ECS. The voltage is incorrect at other terminals on the ECS.

  Repair: Replace the ECS. If the problem is no longer present, reinstall the old ECS. If the problem returns, replace the ECS.

  Stop.

Test Step 8. Check the Voltage at the Sensor Power Supplies.

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

2. Install a Breakout T at the Primary ECM connector P1/J1.

3. Remove the wire 997-OR from P1-36. Remove the wire 993-BR from P1-30.

4. Remove the wire A700-OR from P1-35. Remove the wire 998-BR from P1-29.

5. Turn the ECS to the STOP position.

   Note: If a remote START/STOP switch is installed, the remote START/STOP switch must be in the COOL/STOP position.

6. Measure the voltage between wire 997-OR and wire 993-BR.

7. Measure the voltage between wire A700-OR and wire 998-BR.

   Note: If you remove the sensor common from the ECM, an open circuit diagnostic code will be generated for all sensors that use the sensor common. Troubleshoot the original code. Delete the logged diagnostic codes when you are finished.

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

9. Remove the Breakout T and replace all wires.

Expected Result:

The voltage should be 5.00 ± 0.2 VDC between wire 997-OR and wire 993-BR. The voltage should be 8.00 ± 0.4 VDC between wire A700-OR and wire 998-BR.

Results:

• OK - The sensor power supplies are functioning properly. The ECM is powered up. The problem is not in the electrical system. There may be a mechanical problem. Stop.

• Not OK - If the ECM is getting the correct voltage at the + Battery terminal, but the ECM does not supply the correct voltages to the sensor supplies, replace the ECM.

  Repair: Perform the diagnostic procedure Troubleshooting, "Replacing the ECM".

  Stop.