VENT 0551990 - Caterpillar

System Operation Description:The Primary Electronic Control Module (ECM) receives four input signals from the Engine Control Switch (ECS). The input signals allow the ECM to determine the mode of operation. The ECS can operate in four modes: OFF/RESET, MAN/START, COOLDOWN/STOP and AUTO.When the ECS is set to the OFF/RESET position, the START/RUN/STOP INPUT and the AUTO input are open. The ECM is not powered. Engine operation will stop when the ECS is switched to this position.When the ECS is set to the AUTO position, the START/RUN/STOP INPUT is open and the AUTO input is low. The ECM is powered. If the remote START/STOP Switch is closed, the engine start sequence will begin.When the ECS is set to the MAN/START position, The START/RUN/STOP INPUT is low and the ECS in AUTO input is open. The ECM will begin the engine start sequence.When the ECS is set to the COOLDOWN/STOP position, the START/RUN/STOP INPUT and the ECS in AUTO input are open. After the engine cooldown, the ECM will shut down the engine.If the signals from the START/RUN/STOP INPUT are opposite, the ECM determines that one of the signals is faulty. The ECM ignores the signals until power is cycled to the ECM.If this occurs, the engine must be cranked manually. Use the Manual Crank Switch which is located inside the Instrument Panel. When the engine is shut down, the ECS must be placed in the OFF/RESET position. This will disconnect power to the ECM. A CID-FMI will be active until the ECM is powered down. The status for the ECS will display "ABNORMAL DATA" until power to the ECM is cycled.If you close the remote START/RUN/STOP switch and the ECS is in the AUTO position, the engine will start. The status for the ECS will display "ON" or "OFF". This parameter is available on the Caterpillar Electronic Technician (ET) only when the ECS is in the AUTO position.Note: Turn the breaker for the "MAG Relays" to the OFF position for this test. After completing this test, turn the breaker for the "MAG Relays" to the ON position.
Illustration 1 g00720787
Typical exampleTest Step 1. Check for Connector Damage.
Turn the circuit breaker for the battery to the OFF position.
Turn the ECS to the OFF/RESET position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the ECM connector (allen head screw) for the proper torque of 2.25 0.25 N m (20 2 lb in).
Check the customer connector (allen head screw) for the proper torque of 2.25 0.25 N m (20 2 lb in).
Check the harness and the wiring for abrasion and for pinch points.Expected Result:All connectors, pins, and sockets are coupled and/or inserted. The harness and wiring should be free of corrosion, of abrasion or of pinch points.Results:
OK - The connectors and