BOLT 2018034 - Caterpillar

This section contains some general information about the function of typical engine protective devices.The alarms and shutoffs are set at critical operating temperatures, pressures, or speeds in order to protect the engine from damage.An alarm warns the operator when an abnormal operating condition occurs. The shutoffs shut down the engine if a more critical operating condition occurs. The shutoffs help to prevent damage to the engine.Shutoffs may cause unburned gas to remain in the air inlet and in the exhaust manifold.
Unburned gas in the air inlet and exhaust system may ignite when the engine is started. Personal injury and/or property damage may result.Before starting an engine that may contain unburned gas, purge the unburned gas from the air inlet and exhaust system. Refer to the topic on purging unburned gas in the "Starting the Engine" section.
If an engine protective device shuts off the engine, always determine the cause of the shutoff. Always make the necessary repairs before attempting to start the engine. Refer to Troubleshooting, RENR5944.Become familiar with the following information:
Types of the alarms and shutoffs
Locations of the alarm and shutoff controls
Conditions which cause each control to function
Resetting procedure that is required before starting the engineTesting Alarms and Shutoffs
Alarms must function properly in order to provide timely warning to the operator. Shutoffs help to prevent damage to the engine. You cannot determine if the engine protective devices are in good working order during normal operation. Malfunctions must be simulated in order to test the engine protective devices.
During testing, abnormal operating conditions must be simulated.The tests must be performed correctly in order to prevent possible damage to the engine.
Periodic testing of engine protective devices for proper operation is recommended maintenance. To prevent damage to the engine, only authorized service personnel or your Cat dealer should perform the tests.Prevention of Start-up
The engine will not start if any of the conditions that cause a shutoff are present. The following conditions will also prevent starting of the engine:
An input from the driven equipment prevents starting.
An overcrank occurs.If any of these situations occur, the following conditions must be met before the engine can be started:
The condition that prevented starting is not present.
The engine control switch is turned to the "OFF/RESET" position.Setpoints for Alarms and Shutoffs
Some of the setpoints for the alarms and shutoffs can be programmed with the Cat Electronic Technician (ET). Some of the parameters cannot be programmed.The setpoints are programmed at the factory. The status for most of the parameters is ON.For information on programming of parameters, refer to Systems Operation/Testing and Adjusting.The Electronic Control Module (ECM) monitors the operating parameters of the engine. The ECM can initiate responses if a specific engine parameter exceeds an acceptable range. Three possible responses may be available for each parameter. Refer to table 1.
Table 1
Cross-reference for System Response to Event Warning Category Indicators (1), (2), and (3)
Warning Category Indicator System Response Shown on Cat ET System Response Shown on Cat ET Description of the System Response
(1) "Warning " "Least Severe" Warning
(2) "Moderate Severity" "Moderate