RING-GUIDE 4P1379 - Caterpillar

System Operation Description:Use this procedure in order to troubleshoot the electrical system if a problem is suspected with the remote emergency stop switch. Use this procedure if the diagnostic code in Table 1 is active or easily repeated.
Table 1
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 remote emergency stop switch are in the opposite state. The code is logged. The customer's remote emergency stop switch sends two signals to the Electronic Control Module (ECM). The signals are used to determine if the remote emergency stop switch is active. The customer's remote emergency stop switch is active when the switch is in the open state and the two signals are high. The customer's remote emergency stop switch is inactive when the switch is in the closed state and the two signals are held low.If the ECM is powering up and one of the signals from the customer's remote emergency stop switch is in a different state from the other signal, the ECM determines that one of the signals is faulty. If one of the signals from the customer's remote emergency stop switch is in a different state from the other signal, the ECM will generate a diagnostic code that remains active until power to the ECM is cycled. The ECM will not allow the crank cycle to begin if the signals are opposite of each other. The ECM will allow the engine to be started manually in this state.The ECM monitors the inputs from the customer's remote emergency stop signals at all times. If the engine is running and one of the signals from the customer's remote emergency stop switch changes states, the engine will continue to run. The ECM initiates an emergency stop shutdown only when both signals are high during engine operation.Relay "R3A" and relay "R3" are energized through terminal 3 of the diode assembly. Terminal 3 of the diode assembly will energize relay "R3A" and relay "R3" for 1 second. The contacts of relay "R3" keep relay "R3A" and relay "R3" energized until the Engine Control Switch (ECS) is cycled to the OFF/RESET position. The contacts of relay "R3A" energizes the coil of relay "R2A". When relay "R2A" is energized, power is removed from the ECM. The ECM will power down. The injection signals to the injector solenoids will stop.The contacts of relay "R3A" also supply power to terminal 3 of the connector for a timer. When power is applied to terminal 3 of the connector for the timer, the timer will activate. The timer outputs 24 VDC from terminal 6 of the connector for the timer for 2.5 seconds. The 24 VDC from the timer is applied to the coil of the "ASOS" switch and to terminal 2 of the diode assembly. The "ASOS" switch energizes the two air shutoff solenoids. The solenoids trip the air shutoff valves. The 2.5 second time limit for activation of the "ASOS" switch prevents