| Diagnostic Codes Table | ||
| J1939 Code and Description | Conditions which Generate this Code | System Response |
| 337-2 Engine Auxiliary Engine Shutdown Switch : Erratic, Intermittent, or Incorrect | The two inputs from the emergency stop switch are in the opposite state. | The code is logged. |
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.
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 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. Manually open the air shutoff valve in order to start the engine.
Note: The air shutoff is optional. Set the programmable parameter with Caterpillar Electronic Technician (ET) in order to enable the air shutoff.
The 970-31 Engine Auxiliary Engine Shutdown Switch event code 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 3 seconds in order to clear this event.
| |
| Illustration 1 | g03323410 |
|
Emergency stop schematic | |
| |
| Illustration 2 | g03323450 |
|
Terminal locations at the P1 ECM connector (P1-5) Digital return (P1-23) E-Stop 1 (P1-28) E-Stop 2 | |
| Troubleshooting Test Steps | Values | Results |
|---|---|---|
1. Inspect the Electrical Connectors and the Wiring A. Turn the main disconnect switch to the OFF position. B. Thoroughly inspect the ECM connectors. Also, inspect the connectors at the air shutoff mechanism that are for the solenoids. Also, inspect the switches for the air shutoff. Refer to Troubleshooting, "Electrical Connectors - Inspect" C. Perform a D. Check the allen head screw on each ECM connector for the proper torque. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values. E. Check the harness and the wiring for abrasion and for pinch points from the air shutoff solenoid to the ECM. |
Connectors |
Results: The connectors and wiring appear to be OK. Proceed to Test Step 2 Results: The connectors and/or wiring are not OK. Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are coupled. Verify that the repair eliminated the problem. |
2. Check for Logged Codes A. Connect Cat ET to the service tool connector. B. Restore the electrical power to the ECM. C. Start Cat ET D. Check for an active 337-2 code. Note: Wait at least 30 seconds in order for diagnostic codes to become active. - Restore the wiring to the original configuration. |
Codes |
Results: A 337-2 code is not active. Proceed to Test Step 4. Results: A 337-2 code is active. Repair: The wires between the ECM and the remote e-stop are in opposite states. Proceed to Test Step 3. |
3. Check for an Open Circuit A. Disconnect the J1/P1 ECM connector. B. Measure the resistance between P1-23 at the ECM connector and terminal 2 at the emergency stop switch. C. Measure the resistance between P1-28 at the ECM connector and terminal 2 at the emergency stop switch. |
Open Circuit |
Results: The measurements do not indicate an open circuit. Proceed to Test Step 4. Results: At lease one of the measurements indicate an open circuit Repair: Determine the cause of the open circuit. Repair the problem, when possible. Replace parts, if necessary. Verify that the repair eliminates the problem. |
4. Check the status while the Remote Emergency Stop Switch is Active A. Restore electrical power to the ECM. B. Stat Cat ET. C. Observe the status of the remote emergency stop switch using Cat ET. D. Activate the emergency stop switch. If multiple remote emergency stop switches have been installed, ensure that any other remote emergency stop switch has not been activated. |
ON |
Results: The status of the emergency stop switch reads ON. The switch is working properly. Proceed to Test Step 5. Results: The status of the emergency stop switch does not read ON. Proceed to Test Step 6. |
5. Check the Status while the Remote Emergency Stop Switch is Not Active A. Deactivate the remote emergency stop switch. Note: Ensure that the solenoid valves retract and that the air shutoff valves are open. B. Observe the status of the remote emergency stop switch using Cat ET. |
OFF |
Results: The status of the remote emergency stop switch displays OFF. Repair: The remote emergency stop switch is functioning properly. There may be an intermittent problem. If the problem is intermittent, refer to Troubleshooting, "Electrical Connectors - Inspect". Results: The status of the remote emergency stop switch does not display OFF. Proceed to Test Step 6. |
6. Check for Proper Operation of the ECM A. Disconnect the J1/P1 ECM connectors. B. Fabricate a jumper wire that is long enough to use as a test lead at the ECM connector. Crimp a connector socket to one end of the jumper wire. C. Remove the P1-23 and P1-28 wires from terminal location at the ECM connector. Install the jumper wire into the P1-23 and P1-28 terminal locations. D. Connect the J1/P1 ECM connectors. E. Restore the electrical power to the ECM. F. Measure the voltage between the jumper wire and the engine ground stud while you place the remote emergency stop switch in the STOP position. I. Turn the main disconnect switch to the OFF position. Restore the wiring to the original configuration. |
ECM |
Results: When the remote emergency stop switch is placed in the STOP position, the voltage is 24 ± 3 VDC for one second. Repair: If the status of the emergency stop is active and the remote emergency stop switch is not activated, the likely cause is an open circuit in the digital wire. Check the wire for continuity between the remote emergency stop switch and the ECM. Results: When the remote emergency stop switch is placed in the STOP position, the voltage is not 24 ± 3 VDC for one second. Repair: The ECM is not reading the correct status for the switches. Replace the ECM. Refer to Troubleshooting, "Test ECM Mode". Note: Before you consider replacing the ECM, consult with the Dealer Solutions Network (DSN) for assistance. Verify that the repair eliminates the problem. |
If the procedure did not correct the issue, contact your Cat Dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).