3512B Marine Auxiliary Engine Caterpillar

During a remote shutdown, the emergency stop switch sends two signals to the Electronic Control Module (ECM). The signal is used to determine if the emergency stop switch is active. If the remote emergency stop button is activated, the fuel is shut off and the air shutoff relay is activated. The Secondary ECM will hold the relays active for 1.5 seconds.

The remote emergency stop switch is active, when the signals are open.

The remote emergency stop switch is inactive, when the signals are closed.

When a signal from the remote emergency stop switch is received, the ECM will activate the air shutoff solenoid. The ECM will set the duration of fuel injection to 0. The engine will not start until the remote emergency stop switch is closed. The engine will not start until the engine rpm equals 0. The engine will not start until the power to the ECM has been reset.

The air shutoff relay can also be activated without the aid of the ECM. When the emergency stop on the engine instrument panel is depressed, the air shutoff relay is activated. The air shutoff timer will allow the air shutoff relay to deactivate after 2.5 seconds in order to prevent damage to the air shutoff solenoids.

The engine will not be able to start when the emergency stop switch is activated.

Regardless of the reason for activation, the Engine Control Switch (ECS) must be turned to the OFF/RESET position for three seconds in order to reset the ECM and the air shutoff timer.

Illustration 1	g00925182

Test Step 1. Check for Connector Damage

1. Turn BATTCB to the OFF position.

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

3. Check connectors and associated wiring for the following problems: damage, corrosion, abrasion and incorrect attachment.

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 free of problems. Proceed to test step 2.

• Not OK - The connectors and wiring are not free of problems.

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

  Stop.

Test Step 2. Check the Status of the Switch.

1. Turn the circuit breaker for the battery to the ON position.

2. Turn the ECS to the STOP position.

3. Activate the emergency stop switch.

4. Connect the Caterpillar Electronic Technician (ET) to the service tool connector.

5. Observe the status of the emergency stop switch on the Cat ET.

Expected Result:

The parameter for the emergency stop switch should read "ON".

Results:

• OK - The parameter for the emergency stop switch displays "ON". The emergency stop switch is working correctly. Proceed to test step 3.

• Not OK - The parameter for the emergency stop switch does not display "ON". Proceed to test step 4.

Test Step 3. Check the Status of the Switch.

1. Deactivate the emergency stop switch.

Expected Result:

The parameter for the emergency stop switch should read "OFF".

Results:

• OK - The parameter for the emergency stop switch displays "OFF". The emergency stop switch is working correctly.

  Repair: The repair is complete.

  Stop.

• Not OK - The parameter for the emergency stop switch does not display "OFF". Proceed to test step 4.

Test Step 4. Test the ECM.

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

2. Disconnect P1 from the ECM. Remove P1-29, P1-02 and P1-24.

3. Locate a suitable jumper wire.

4. Insert the jumper wire at P1. Connect P1-02 and P1-24 to P1-29.

5. Turn the ECS to the STOP position.

6. Observe the parameters for the emergency stop on the Cat ET.

7. Turn the ECS to the OFF/RESET position. Remove the jumper wire and reinstall all wires.

Expected Result:

The parameter for the emergency stop switch should display "ON" when the jumper is installed. The parameter for the emergency stop switch should display "OFF" when the jumper is removed.

Results:

• OK - The parameter for the emergency stop switch displays "ON". Proceed to test step 5.

• Not OK - The parameter for the emergency stop switch does not display "ON".

  Repair: Replace the ECM. Perform a diagnostic functional test. Perform the diagnostic procedure Troubleshooting, "Replacing the ECM".

  Stop.

Test Step 5. Check the Switches and the Wiring.

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

2. Activate the emergency stop switch.

3. Measure the resistance between the digital sensor return P1-29 and the remote emergency stop switch 1 P1-02.

4. Measure the resistance between digital sensor return P1-29 and the remote emergency stop switch 2 P1-24.

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 6.

• Not OK - The resistance is less than 20,000 Ohm. There is a short circuit in the emergency stop switch.

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

  Stop.

Test Step 6. Deactivate the Switch.

1. Deactivate the emergency shutdown switch.

2. Measure the resistance between digital sensor return P1-29 and the remote emergency stop switch 1 P1-02.

3. Measure the resistance between the digital sensor return P1-29 and the remote emergency stop 2 P1-24.

Expected Result:

The resistance should read less than 10 Ohms.

Results:

• OK - The resistance is less than 10 Ohms. The emergency shutdown switch is OK.

  Repair: The repair is complete.

  Stop.

• Not OK - The resistance is greater than 10 Ohms. There is an open circuit in the emergency shutdown switch.

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

  Stop.