HARNESS ASSEMBLY-TRANSMISSION JUMPER 2398155 - Caterpillar

The Electronic Control Module (ECM) receives two signals from the emergency stop switch. The signals allow the ECM to determine the status of the emergency stop switch. The ECM will shut down the engine when both of the signals are open. When both of the signals are connected to the digital return the emergency stop switch is not active and the engine will run. Refer to Illustration 1.If two different signals are detected during the powerup, the ECM will determine that one of the signals is incorrect. A diagnostic code will be logged and a diagnostic code will remain active. The engine will continue to run when the ECM detects two different signals. If both of the signals are open, the engine will stop.The customer can install multiple emergency stop switches. When the start/run/stop switch is turned to the ON position, the engine will begin the sequence for start-up. When the emergency stop switch is activated the ECM will stop firing the injectors. The engine will stop. When an emergency stop signal is received by the ECM, the ECM will activate the output for the solenoid valve that controls the air shutoff valve. When the solenoid valve activates, the air shutoff valve closes removing the intake air to 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 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.
Illustration 1 g01212645
Typical schematic
Illustration 2 g01212647
P1 ECM connector
(P1-5) Digital return
(P1-21) Start/Run/Stop input 1
(P1-22) Start/Run/Stop input 2
(P1-23) Emergency stop signal "C"
(P1-28) Emergency stop signal "D"
(P1-52) +Battery
(P1-53) +Battery
(P1-55) +Battery (ECM)
(P1-56) Air shutoff (NO)
(P1-63) −Battery
(P1-65) −Battery
(P1-70) Keyswitch
Illustration 3 g01212650
Customer connector
(Terminal 01) +Battery
(Terminal 02) +Battery
(Terminal 04) Air shutoff
(Terminal 09) Digital return
(Terminal 16) Emergency stop signal "D"
(Terminal 17) Emergency stop signal "C"
(Terminal 23) Start/Run/Stop input 1
(Terminal 24) Start/Run/Stop input 2
(Terminal 27) Keyswitch
(Terminal 34) −Battery
(Terminal 35) −Battery Test Step 1. Check for an Active Diagnostic Code
Turn the main disconnect switch to the ON position.
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 emergency stop switch are in opposite states. Check the wires for an open circuit.
Turn the main disconnect switch to the OFF position.
Disconnect the J1/P1 ECM connector.
Measure the resistance between P1-23 at ECM connector P1 and terminal 2 at the emergency stop switch.
Measure the resistance between P1-28 at ECM connector P1 and terminal 2 at the emergency stop switch. If the resistance measurement indicates an open circuit, repair the wires