The user defined shutdown can be connected to a device in the electrical system that would shut down the engine for any reason. When the signal is active, an event code is logged in memory and the Electronic Control Module (ECM) stops fuel injection.
The user defined switch "Active State" is used in order to program the ECM to recognize the configuration of the shutdown switch. The input can be programmed to the following configurations:
- "Active-High" (Switch to +Battery)
- "Active-Low" (Switch to -Battery)
Note: The input must be pulled below 0.5 VDC before the ECM will recognize the shutdown signal. The signal must be above 5 VDC before the ECM will recognize the warning signal.
E271-1 (user defined switch warning) will be displayed when the programmable monitoring system parameter for the warning for the user defined switch is "Enabled" and the user defined switch input is active.
E271-3 (user defined switch shutdown) will be displayed when the programmable monitoring system parameter for the shutdown for the user defined switch is "Enabled" and the user defined switch input is active.
After the installation status and the active state has been programmed, the engine monitoring system must be programmed for the "Warning" and "Shutdown" delay time.
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| Illustration 1 | g01066057 |
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User defined shutdown switch in the OFF position ("Active-Low" configuration) | |
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| Illustration 2 | g01072522 |
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User defined shutdown switch in the ON position ("Active-High" configuration) | |
Test Step 1. INSPECT ELECTRICAL CONNECTORS AND WIRING
- Turn the Engine Control Switch (ECS) to the OFF/RESET position.
- Thoroughly inspect the J2/P2 ECM connector, the J3/P3 Machine interface connector, and the connection to the user defined shutdown device (switch). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
- Check the harness and wiring for abrasion and for pinch points from the user defined shutdown device to the ECM.
Expected Result:
All connectors, pins, and sockets are completely inserted and coupled. The harness and wiring are free of corrosion, of abrasions, and of pinch points.
Results:
- OK - Proceed to Test Step 2.
- Not OK -
Repair: Repair the circuit.
Verify that the repair eliminates the problem.
STOP
Test Step 2. VERIFY THE OPERATION OF THE USER DEFINED SHUTDOWN SWITCH
- Connect the Caterpillar Electronic Technician (ET) to the service tool connector.
- Turn the circuit breaker for the battery to the ON position.
- Turn the ECS to the STOP position.
- Observe the status of "User Defined Switch Active State" on Cat ET.
- Observe the configuration of the shutdown switch on Cat ET. Verify that the "User Defined Switch Installation Status" is programmed to "Installed".
- Observe the "Configuration" screen of Cat ET. Verify that the "User Defined Switch Active State" is programmed to "Active-Low" or that the status is programmed to "Active-High".
- Select the "Caterpillar Monitoring System" and program the "User Defined Switch Active State Warning" to the ON position. Set the time delay to one second. Program the "User Defined Active State Shutdown" to the OFF position.
- Access the status screen on Cat ET and monitor the "User Defined Shutdown Switch". Start the engine. Run the engine above the low idle speed. Toggle the user defined shutdown switch from the ON to OFF and back to the ON position.
Expected Result:
E271-1 user defined shutdown warnng is active when the shutdown switch is in the ON position.
When the shutdown switch is in the OFF position, E271-1 is not active.
The status of the "User Defined Switch Installation Status" is programmed to "Installed". Also, the "User Defined Switch Active State" is programmed to "Active-Low" or the "User Defined Switch Active State" is programmed to "Active-High".
Results:
- OK - Proceed to Test Step 4.
- Not OK - Proceed to Test Step 3.
Test Step 3. CHECK THE HARNESS FOR SHORTS
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| Illustration 3 | g01066369 |
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P1 ECM connector | |
- Disconnect ECM connector J1/P1.
- Measure the resistance between P1:23 (User defined shutdown input) and engine ground. Measure the resistance between P1:23 (User defined shutdown input) and all other pins in P1 ECM connector.
- Measure the resistance between P1:29 (Digital return) and engine ground. Measure the resistance between P1:29 (Digital return) and all other pins in P1 ECM connector.
Expected Result:
The resistance is greater than 20,000 Ohms.
Results:
- OK - Proceed to Test Step 4.
- Not OK - There is a short circuit in the harness or a user defined shutdown device is activating the shutdown feature.
Repair: Ensure that a user defined shutdown device is not activating the shutdown feature.
Repair the circuit.
Verify that the repair eliminates the problem.
STOP
Test Step 4. CHECK THE RESISTANCE THROUGH THE HARNESS
- Turn the keyswitch to the OFF/RESET position.
- Disconnect the J1/P1 ECM connector.
- Use a suitable piece of wire to short J3:26 (User defined shutdown input) to engine ground. Verify that the user defined shut down switch is set to "Active-Low".
- Measure the resistance between P1:23 (User defined shutdown input) and engine ground.
- Measure the resistance between J3:26 and all the other pins in P3 Machine interface connector.
- Remove the wire short.
Expected Result:
The resistance is less than 10 Ohms when the terminal is grounded.
Results:
- OK - The resistance is within acceptable limits. Proceed to Test Step 5.
- Not OK - There is an open circuit or excessive resistance in the harness.
Repair: Repair the circuit.
Verify that the repair eliminates the problem.
STOP
Test Step 5. SHORT THE INPUT AT THE ECM
- Disconnect P1 ECM connector.
- Use a suitable piece of wire to short P1:23 (User Defined Shutdown) to engine ground. Verify that the user defined shut down switch is set to "Active-Low".
- Observe the status of "User Shutdown" on Cat ET.
Expected Result:
The status is "On" when the wire short is in place. The status should be "Off" when the wire short is removed.
Results:
- OK - The user defined shutdown switch is working properly.
STOP
- Not OK - The correct switch input appears at the ECM, but the ECM is not reading the switch input properly.
Repair: Verify your results. Replace the ECM. Refer to Troubleshooting, "Replacing the ECM" before replacing the ECM.
STOP