HOSE 3991376 - Caterpillar

Probable Causes
The "Emergency Stop" button is pressed.
The circuit for the emergency stop is faulty.
The normal stop switch that is installed by the customer is activated.
The circuit for the normal stop switch is faulty.
Either switch is activated by excessive vibration.Recommended Repairs
The ignition is immediately terminated when the emergency stop button is pressed. Unburned gas remains in the air inlet and exhaust system.
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 was stopped by terminating the ignition, purge the unburned gas from the air inlet and exhaust system. Refer to "Unburned Gas - Purge".
Talk to the operator
Ask the operator if the stop was intentional. Make sure that the reason for the stop has been corrected. Reset the control system. Resume normal operation.If the stop was accidental, reset the control system. Resume normal operation.Check the Circuit for the Stop Switches
Note: The circuit for the normal stop switch and the circuit for the emergency stop switch must remain closed in order for the engine to run.Inspect the wiring between the switches and the connector of the electronic control module. Look for damage and/or corrosion. Refer to Troubleshooting, "Inspecting Electrical Connectors".For the emergency stop switch, close the switch and check the resistance between terminals P1-22 and P1-31.For the normal stop switch, close the switch and check the resistance between terminals P1-23 and P1-31.The correct resistance between the terminals is less than 5 Ohms. If the resistance is greater than 5 Ohms, locate the source of the excessive resistance. Make repairs, as needed.Inspect the Stop Switches
Inspect the stop switches for evidence of damage that has been caused by vibration. Disassemble the switches. Inspect the components for looseness, for cracks, and for abrasion. Use an ohmmeter and toggle the switches in order to check for proper electrical operation.Replace any faulty components.