3500B Engines for Caterpillar Built Power Modules with the ADEM 3 Electronic Control Module Caterpillar

Use this procedure in order to troubleshoot the emergency stop system or use this procedure if the diagnostic code in Table 1 is active or easily repeated.

The Electronic Control Module (ECM) receives two signals from the emergency stop switch. The signals allow the ECM to determine the status of the emergency stop switch. The ECM will shut down the engine when both of the signals are open. When both of the signals are connected to the −Battery the emergency stop switch is not active and the engine will run. Refer to Illustration 1.

If two different signals are detected during the powerup, the ECM will determine that one of the signals is incorrect. A diagnostic code will be logged and a diagnostic code will remain active. The engine will continue to run when the ECM detects two different signals. If both of the signals are open, the engine will stop.

The customer can install multiple emergency stop switches. When the Engine Control Switch (ECS) is turned to the ON position, the engine will begin the sequence for start-up. When the emergency stop switch is activated the ECM will stop firing the injectors. The engine will stop. When an emergency stop signal is received by the ECM, the ECM will activate the output for the solenoid valve that controls the air shutoff valve. When the solenoid valve activates, the air shutoff valve closes removing the intake air to the engine. The air shutoff valve must be manually opened in order to start the engine.

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

A E264-3 Emergency Stop Activated will be set when the remote emergency stop switch is activated. This event will prevent engine operation. Electrical power to the ECM must be removed for three seconds in order to clear this event.

Illustration 1	g01443822
Typical schematic

Illustration 2	g01382204
P1 ECM connector (P1-23) Emergency stop signal 1 (P1-28) Emergency stop signal 2

Illustration 3	g01445050
P2 ECM connector (66) Digital return

Illustration 4	g01382207
Connector for the generator (Terminal 19) Emergency stop signal 1 (Terminal 17) Emergency stop signal 2 (Terminal 15) Digital return

Illustration 5	g01234146
Location of ECM connectors

Test Step 1. Check for an Active Diagnostic Code

1. Turn the main disconnect switch to the ON position.

2. Start Cat ET.

3. Check for an active 337-2 diagnostic code.

Expected Result:

The 337-2 diagnostic code is not active.

Results:

• OK - The 337-2 diagnostic code is not active. Proceed to Test Step 3.

• Not OK - The 337-2 diagnostic code is active.

  Repair: If the diagnostic code 337-2 is active, the wires between the ECM and the emergency stop switch are in opposite states. Check the wires for an open circuit.

  1. Turn the main disconnect switch to the OFF position.

  2. Disconnect the J1/P1 ECM connector.

  3. Measure the resistance between P1-23 at ECM connector P1 and terminal 2 at the emergency stop switch.

  4. Measure the resistance between P1-28 at ECM connector P1 and terminal 4 at the emergency stop switch.
  If a resistance measurement indicates an open circuit, repair the wires and/or connectors between the emergency stop switch and the ECM.

  STOP

Test Step 2. Check the Status while the Emergency Stop Switch is Not Active

1. Deactivate the emergency stop switch.

2. Remove electrical power from the ECM for 3 seconds.

3. Restore electrical power to the ECM.

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

Expected Result:

The status for the emergency stop switch reads "OFF".

Results:

• OK - The status for the emergency stop switch reads "OFF". Proceed to Test Step 3.

• Not OK - The status for the emergency stop switch does not display "OFF". Proceed to Test Step 4.

Test Step 3. Check the Status while the Emergency Stop Switch is Active

1. Activate the emergency stop switch. If multiple emergency stop switches have been installed, ensure that any other emergency stop switch has not been activated.

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

Expected Result:

The status for the emergency stop switch reads "ON".

Results:

• OK - The status for the emergency stop switch reads "ON".

  Repair: The emergency stop switch is functioning correctly. There may be an intermittent problem. If the problem is intermittent, refer to Troubleshooting, "Electrical Connectors - Inspect".

  STOP

• Not OK - The status for the emergency stop switch does not read "ON". Proceed to Test Step 4.

Test Step 4. Test the Operation of the Emergency Stop Switch

1. Disconnect the wires for the digital return from terminal 2 and terminal 4 of the emergency stop switch.

2. Use Cat ET to read the status of the emergency stop switch.

3. Install jumper wires between the digital return wires and terminals 1 and 3 at the emergency stop switch.

4. Remove electrical power from the ECM for 3 seconds.

5. Restore electrical power to the ECM.

6. Use Cat ET to read the status of the emergency stop switch.

7. Remove electrical power from the ECM. Restore the wiring and the connectors to the original configuration.

Expected Result:

The status for the emergency stop switch reads "ON" when the digital return wires are disconnected from the switch. The status for the emergency stop switch reads "OFF" when the jumper wires are installed.

Results:

• OK - The status for the emergency stop switch is displaying the proper states. The problem is not with the ECM or the wiring to the ECM.

  Repair: Replace the emergency stop switch. Verify that the problem is resolved.

  STOP

• Not OK - The status for the emergency stop switch is not displaying the proper states. The problem is in the wiring between the emergency stop switch and the ECM. Proceed to Test Step 5.

Test Step 5. Install Jumper Wires at the Inputs to the ECM from the Emergency Stop Switch

1. Turn the main disconnect switch to the OFF position.

2. Disconnect ECM connector J1/P1.

3. Remove wire F715-BK(Black) from the ECM connector P1-23. Install a wire jumper with a socket on one end into P1-23. Do not allow the end of the wire jumper to contact any other wire in the harness or engine ground.

4. Remove wire F719-BK(Black) from the ECM connector P1-28. Install a wire jumper with a socket on one end into P1-28. Do not allow the end of the wire jumper to contact any other wire in the harness or engine ground.

5. Connect ECM connector J1/P1.

6. Disconnect ECM connector J2/P2.

7. Remove the digital return wire E998-BK(Black) from the ECM connector P2-66. Install a wire jumper with a socket on one end into P2-66. Do not allow the end of the wire jumper to contact any other wire in the harness.

8. Connect ECM connector J2/P2.

9. Connect the wire jumpers in P1-23 and P1-28 to the wire jumper in P2-66 digital return.

10. Turn the main disconnect switch to the ON position.

11. Use Cat ET to read the status of the emergency stop switch.

12. Disconnect the wire jumpers in P1-23 and P1-28 from the wire jumper P2-66 digital return. Do not allow any of the wire jumpers to contact any other wire in the harness or engine ground.

13. Use Cat ET to read the status of the emergency stop switch.

14. Turn the main disconnect switch to the OFF position. Restore the wiring and the connectors to the original configuration.

Expected Result:

The status for the emergency stop switch reads "ON" when the jumper wire is not installed. The status for the emergency stop switch reads "OFF" when the jumper wire is installed.

Results:

• OK - The status for the emergency stop switch is displaying the proper states. The problem is not with the ECM.

  Repair: If the emergency stop is active and the emergency stop switch is not activated, the likely cause is an open circuit in the return wire from the emergency stop switch to the −Battery. Check the wire for continuity between the emergency stop switch and the Battery.

  STOP

• Not OK - The status for the emergency stop switch is not displaying the proper states.

  Repair: Replace the ECM. Refer to Troubleshooting, "ECM - Replace".

  STOP