3512B Engine for SPF343, SPS343, and SPT343 Pumpers Caterpillar

The Electronic Control Module (ECM) has the ability to stop the engine by cutting off the air supply in an emergency situation. The ECM activates the air shutoff solenoid in order to close the air path. There are two conditions which cause the engine control to activate the air shutoff solenoid.

The first condition occurs when the operator initiates an emergency shutdown. When the operator activates the "Emergency Kill" switch on the "Universal Remote Control Panel" the "Emergency Kill Relay (EKR)" in the Junction Box will energize. A set of normally closed contacts from the "EKR" opens allowing the two emergency shutdown signals to the ECM to go high. When the shutdown is recognized, fuel is shut off and the air shutoff solenoid is activated. There are two normally closed switches in series with the set of normally closed contacts from the "EKR". The two switches are the "Left Shut Off Switch (LSOS)" and the "Right Shut Off Switch (RSOS)". When the Air Shutoff Solenoids are activated the "LSOS" and the "RSOS" will open. Ensure that BOTH of the air shutoffs are manually reset after an Emergency Stop in order to close the "LSOS" switch and the "RSOS" switch.

The second condition is for an engine overspeed. Engine overspeed can be a real overspeed condition. Overspeed can be obtained by using the overspeed verify switch.

Regardless of the reason for activation, the main power to the ECM must be turned OFF for three seconds in order to reset the engine control.

Note: Ensure that BOTH of the air shutoffs are manually reset after an Emergency Stop in order to start the engine again.

Note: The Air Shutoff is optional. A programmable parameter needs to be set with the Caterpillar Electronic Technician (ET) in order to enable the air shutoff.

Illustration 1	g00853971
Typical schematic

Test Step 1. Check for Connector Damage.

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Prevent sparks near the batteries. Sparks could cause vapors to explode. Do not allow jumper cable ends to contact each other or the engine.

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

2. Disconnect the main power.

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 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. Test the Output to the Air Shutoff Solenoid.

1. Start the Cat ET.

2. Connect the main power.

3. Select "Diagnostic Tests" from the "Diagnostic" menu in order to access the override for the air shutoff on the Cat ET. Activate the override for the air shutoff.

4. Monitor the air shutoff solenoid.

5. Deactivate the override for the air shutoff.

Expected Result:

The air shutoff solenoid should activate. The Cat ET screen should indicate that the air shutoff is "ON".

Results:

• OK - The air shutoff solenoid activates. The Cat ET screen indicates that the air shutoff is "ON".

  Repair: The air shutoff is operating correctly.

  Stop.

• Not OK - The air shutoff solenoid does not activate. Proceed to test step 3.

• Intermittent Problem - The air shutoff system is operating erratically.

  Repair: Perform the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".

  Stop.

Test Step 3. Check the Air Shutoff Solenoid.

1. Disconnect the main power.

2. Disconnect connector J121/P121 at the air shutoff solenoid.

3. Connect a voltage test lamp on the connector for the air shutoff P121 between pin C and pin B.

4. Connect the main power.

5. Access the override for the air shutoff on the Cat ET. Activate the override for the air shutoff.

6. Monitor the voltage test lamp.

7. Deactivate the override for the air shutoff solenoid.

Expected Result:

The voltage test lamp should illuminate when the override for the air shutoff is activated.

Results:

• OK - The voltage test lamp illuminates when the override for the air shutoff is activated.

  Repair: Replace the air shutoff solenoid. Ensure that the problem is no longer present.

  Stop.

• Not OK - The voltage test lamp does not illuminate when the override for the air shutoff is activated. Proceed to test step 4.

Test Step 4. Check the Signal from the ECM to the Air Shutoff Solenoid.

1. Disconnect the main power.

2. Disconnect the ECM connector J2/P2.

3. Remove the wire G971-BR from ECM connector P2-19. Install a wire jumper into the socket for P2-19.

4. Connect a voltage test lamp between the wire jumper in ECM connector P2-19 and the - Battery terminal.

5. Connect the main power.

6. Access the override for the air shutoff on the Cat ET. Activate the override for the air shutoff.

   Note: This test will cause a 446-05 CID-FMI to be logged. Be sure to delete this CID-FMI when this test is completed.

7. Monitor the voltage test lamp.

8. Disable the override for the air shutoff.

9. Disconnect the main power. Remove the wire jumper. Reinstall all wires. Reconnect the ECM connector.

10. Disconnect the Cat ET.

Expected Result:

The voltage test lamp should illuminate when the override for the air shutoff is activated.

Results:

• OK - The voltage test lamp illuminates when the override for the air shutoff is activated. The problem appears to be in the wiring between the ECM and the air shutoff solenoid.

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

  Stop.

• Not OK - The voltage test lamp does not illuminate when the override for the air shutoff is activated. The voltage is not within the correct range.

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

  Stop.