11794M Mercury FLOAT PIN

Table 1
Diagnostic Codes Table
Description Conditions which Generate this Code System Response
337-2 Incorrect Remote E-Stop Switch inputs The two inputs from the remote emergency stop switch are in the opposite state. The code is logged. The 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 remote emergency stop switch is active when the switch is in the open state and the two signals are high. The 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 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 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 remote emergency stop signals at all times. If the engine is running and one of the signals from the 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.When an emergency stop signal is received by the ECM, the ECM will activate the output for the relay that controls the air shutoff valve. When the solenoid valve activates, the air shutoff valve closes removing the intake air from the engine.The switch at the air shutoff valve allows the ECM to determine if the air shutoff valve is open or closed. If the shutoff valve is closed, the switch is in the closed position and the ECM will not start the engine. The air shutoff valve must be manually opened in order to start the engine.The ECM will not allow the starting sequence to begin when the remote emergency stop switch is activated. The engine will not be able to restart until the following conditions are met:
The engine rpm must equal zero.
The remote emergency stop inputs must go low.
The ECM has been reset.The electrical power to the input for the keyswitch must be turned OFF for three seconds in order to reset the engine ECM after an emergency stop condition.Note: If one of the signals from the remote emergency stop switch is in a different state from the other signal, the Caterpillar Electronic Technician (ET) will display the warning "INVALID DATA".
Illustration 1 g01218360
Typical schematic
Illustration 2 g01218361
P1 ECM connector
(P1-5) Digital return
(P1-23) Emergency stop signal "C"
(P1-28) Emergency stop signal "D"
Illustration 3 g01218363
"Connector A"
(Terminal 21) Emergency stop signal "D"
(Terminal 23) Emergency stop signal "C"
(Terminal 25) Digital return
Illustration 4 g01218364
Customer connector
(Terminal 20) Digital return
(Terminal 33) Emergency stop signal "C"
(Terminal 34) Emergency stop signal "D"
Illustration 5 g01234146
Location of ECM connectors
Test Step 1. Check for an Active Diagnostic Code
Restore electrical power to the ECM.
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 wires between the ECM and the remote emergency stop switch are in opposite states. 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 2 at the remote emergency stop switch.
Measure the resistance between P1-28 at ECM connector P1 and terminal 2 at the remote emergency stop switch. If the resistance measurement indicates an open circuit, repair the wires and/or connectors between the remote emergency stop switch and the ECM.STOPTest Step 2. Check the Status while the Remote Emergency Stop Switch is Active
Restore electrical power to the ECM.
Start Cat ET.
Observe the status of the remote emergency stop switch on Cat ET.
Activate the remote emergency stop switch. If multiple remote emergency stop switches have been installed, ensure that any other remote emergency stop switch has not been activated. Expected Result:The status for the remote emergency stop switch reads "ON".Results:
OK - The status for the remote emergency stop switch reads "ON". Proceed to Test Step 3.
Not OK - The status for the remote emergency stop switch does not read "ON". Proceed to Test Step 4.Test Step 3. Check the Status while the Remote Emergency Stop Switch is Not Active
Deactivate the remote emergency stop switch. Note: Ensure that the solenoid valves retract and that the air shutoff valves are open.
Observe the status of the remote emergency stop switch on Cat ET. Expected Result:The status for the remote emergency stop switch reads "OFF".Results:
OK - The status for the remote emergency stop switch reads "OFF".Repair: The remote emergency stop switch 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 remote emergency stop switch does not display "OFF". Proceed to Test Step 4.Test Step 4. Test the Operation of the Remote Emergency Stop Switch
Disconnect the wires that are on terminal 1 of the remote emergency stop switch.
Observe the status of the remote emergency stop switch on Cat ET.
Install a jumper wire between the wires from terminal 1 and terminal 2 at the remote emergency stop switch.
Observe the status of the remote emergency stop switch on Cat ET.
Remove electrical power from the ECM. Restore the wiring and the connectors to the original configuration. Expected Result:The status for the remote emergency stop switch reads "ON" when the wires are disconnected from terminal 1 and the jumper wire is not installed. The status for the remote emergency stop switch reads "OFF" when the jumper wire is installed.Results:
OK -