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.
| Diagnostic Codes Table | ||
|---|---|---|
| Description | Conditions which Generate this Code | System Response |
| 337-2 Remote Emergency Stop Switch erratic, intermittent, or incorrect | The two inputs from the emergency stop switch are in the opposite state. | The code is logged. |
The ADEM box receives an emergency stop signal from the main junction box. The signal goes to the terminal strip in the ADEM box. Two separate wires from the terminal strip are wired to the two inputs for the emergency stop switch on the Electronic Control Module (ECM). The signals allow the ECM to determine the status of the "Emergency Kill" button on the control panel. When both of the signals are floating the "Emergency Kill" button is active. When both of the signals are connected to the digital return the "Emergency Kill" button is not active. The ECM will disable injection if the "Emergency Kill" button is active. The ECM will activate the air shutoff solenoid if the "Emergency Kill" button is active. Refer to Illustration 1.
If the two signals are at a different potential, the ECM will determine that one of the signals is incorrect. A diagnostic code will be logged and a diagnostic code will remain active. If the engine is running and the ECM detects a different potential between the two signals, the ECM will continue to enable injection.
When the "Emergency Kill" button on the control panel is activated the master "DCU" energizes the "Emergency Kill Relay (EKR)". The normally closed contacts of the "Emergency Kill Relay (EKR)" open. When the normally closed contacts of the "Emergency Kill Relay (EKR)" open the two inputs for the emergency stop switch will float.
The electrical power to the input for the keyswitch must be turned OFF for fifteen seconds in order to reset the engine ECM after an emergency stop condition.
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| Illustration 1 | g01286272 |
Typical schematic | |
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| Illustration 2 | g01286273 |
P1 ECM connector (P1-5) Digital return (P1-23) Emergency stop signal "C" (P1-28) Emergency stop signal "D" | |
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| Illustration 3 | g01285750 |
Location of ECM connectors | |
Test Step 1. Check for an Active Diagnostic Code
- Turn the "main disconnect switch (MDS)" to the ON position.
- Start Caterpillar Electronic Technician (ET).
- 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 2.
- Not OK - The 337-2 diagnostic code is active.
Repair: If the diagnostic code 337-2 is active, the inputs from the wires between the ECM and the terminal strip in the ADEM box are in opposite states. Check the wires for an open or for a short circuit.
- Check the wires for an open circuit.
- Disconnect the J1/P1 ECM connector.
- Measure the resistance between P1-23 at ECM connector P1 and terminal 102 on the terminal strip.
- Measure the resistance between P1-28 at ECM connector P1 and terminal 102 on the terminal strip.
- If the resistance measurement indicates an open circuit, repair the wire and/or connectors between the terminal strip and the ECM.
- Check the wires for a short circuit.
- Disconnect the J1/P1 ECM connector and the J2/P2 ECM connector.
- Disconnect the wire F715-BK and wire F719-BK from terminal 102 in the ADEM box.
- Measure the resistance between P1-23 and every terminal on ECM connector P1 and ECM connector P2.
- Measure the resistance between P1-23 and engine ground.
- Measure the resistance between P1-28 and every terminal on ECM connector P1 and ECM connector P2.
- Measure the resistance between P1-28 and engine ground.
- If the resistance measurement indicates a short circuit, repair the wire and/or connectors between the terminal strip and the ECM.
STOP
- Check the wires for an open circuit.
Test Step 2. Check the Status while the "Emergency Kill" Button is Active
- Observe the status of the emergency stop on Cat ET.
- Activate the "Emergency Kill" button.
Expected Result:
The status for the emergency stop reads "ON".
Results:
- OK - The status for the emergency stop reads "ON". Proceed to Test Step 3.
- Not OK - The status for the emergency stop does not read "ON". Proceed to Test Step 6.
Test Step 3. Check the Status while the "Emergency Kill" Button is Not Active
- Deactivate the "Emergency Kill" button.
Note: Ensure that the solenoid valves retract and that the air shutoff valves are open.
- Observe the status of the emergency stop on Cat ET.
Expected Result:
The status for the emergency stop reads "OFF".
Results:
- OK - The status for the emergency stop reads "OFF".
Repair: The emergency stop is functioning correctly. There may be an intermittent problem. If the problem is intermittent, refer to Troubleshooting, "Inspecting Electrical Connectors".
STOP
- Not OK - The status for the emergency stop does not display "OFF". Proceed to Test Step 4.
Test Step 4. Check the Emergency Stop Signal in the ADEM Box for an Open Circuit
- Turn the "MDS" to the OFF position.
- Disconnect the wire from the main junction box that is on terminal 101 in the ADEM box.
- Disconnect the wire from the main junction box that is on terminal 102 in the ADEM box.
- Measure the resistance between the wires that were disconnected from terminal 101 and from terminal 102.
- Replace all wires to the original configuration.
Expected Result:
The resistance measurement indicates a short circuit.
Results:
- OK - The resistance measurement indicates a short circuit.
Repair: Check the wire 998-BK for an open circuit between terminal 101 in the ADEM box and the ECM. Check for an open circuit in the wires between terminal 102 in the ADEM box and ECM terminals P1-23 and P1-28.
STOP
- Not OK - The resistance measurement indicates an open circuit. Proceed to Test Step 5.
Test Step 5. Check the Emergency Stop Signal at the Main Junction Box for an Open Circuit
- Disconnect the wire from TB-35 in the main junction box that goes to the ADEM box.
- Disconnect the wire from TB-15 in the main junction box that goes to the ADEM box.
- Measure the resistance between TB-35 and TB-15 in the main junction box.
- Replace all wires to the original configuration.
Expected Result:
The resistance measurement indicates a short circuit.
Results:
- OK - The resistance measurement indicates a short circuit.
Repair: One of the wires between the main junction box and the ADEM box has an open circuit. Repair the wire.
STOP
- Not OK - The resistance measurement indicates an open circuit.
Repair: The contacts of the "Emergency Kill Relay (EKR)" or the "EKR" is not working properly. Repair the wiring to the "EKR" or repair the "EKR".
STOP
Test Step 6. Check the Emergency Stop Signal in the ADEM Box for a Short Circuit
- Turn the "MDS" to the OFF position.
- Disconnect the wire F715-BK and wire F719-BK from terminal 102 in the ADEM box.
- Turn the "MDS" to the ON position.
- Observe the status of the emergency stop on Cat ET.
- Turn the "MDS" to the OFF position.
- Replace all wires to the original configuration.
Expected Result:
The status for the emergency stop reads "ON".
Results:
- OK - The status for the emergency stop reads "ON". Proceed to Test Step 7.
- Not OK - The status for the emergency stop reads "OFF".
Repair: Check the wire F715-BK for a short circuit to engine ground or for a short to a wire in one of the ECM connectors. Check the wire F719-BK for a short circuit to engine ground or for a short to a wire in one of the ECM connectors. Repair the wire.
STOP
Test Step 7. Check the Emergency Stop Signal at the Main Junction Box for a Short Circuit
- Turn the "MDS" to the OFF position.
- Disconnect the wire from TB-35 in the main junction box that goes to the ADEM box.
- Turn the "MDS" to the ON position.
- Observe the status of the emergency stop on Cat ET.
- Turn the "MDS" to the OFF position.
- Replace all wires to the original configuration.
Expected Result:
The status for the emergency stop reads "ON".
Results:
- OK - The status for the emergency stop reads "ON".
Repair: The wiring between the main junction box and the ECM junction box is OK. The contacts of the "Emergency Kill Relay (EKR)" or the "EKR" is not working properly. Replace the "EKR".
STOP
- Not OK - The status for the emergency stop reads "OFF".
Repair: There is short in wire between terminal TB-35 in the main junction box and terminal 102 in the ECM junction box. Repair the wire.
STOP