Start/Run/Stop Switch on Caterpillar ET Software

Start/Run/Stop Switch

Figure 1.1 - Ignition (Run/Stop) and Start Switch

The Electronic Control Module (ECM) receives two input signals from the Start/Run/Stop Switch. The two input signals should have the same logic level. If two different signals are detected during the

powerup, the ECM will determine that one of the signals is incorrect. The duplication of the signals permits the ECM to know if there is a problem in the wiring.

When both of the input signals are high or open, the ECM assumes that the Start/Run/Stop Switch is in the STOP position. When both of the input signals are low or shorted to the (−) Battery terminal, the ECM assumes that the Start/Run/Stop Switch is in the START position. After the Start/Run/Stop Switch is turned to the START position, the ECM will initiate the starting sequence. The ECM will energize the pre-lube system, if the pre-lube system is available and activated. After the pre-lube cycle is completed, the ECM will energize the starting solenoids for the starting motors. If both of the signals go high or open while the Engine is running, the Engine will stop.

Figure 1.2 - Startup Mode (Overcrank)

If the Engine is running and one of the inputs from the Start/Run/Stop Switch changes states, the ECM will ignore the inputs from the Start/Run/Stop Switch until power is cycled to the ECM. If this occurs, you must use the Emergency Stop Switch or you must disconnect the power to the ECM in order to shut down the Engine.

If the inputs from the Start/Run/Stop Switch are in opposite states at the beginning of a crank cycle, the ECM will not initiate the crank cycle. If this condition occurs, the Engine may be started by using the manual crank switch. If you start the Engine with the manual crank switch, you must use the Emergency Stop Switch or you must disconnect the power to the ECM in order to shut down the Engine. A Diagnostic code will be logged and a Diagnostic code will be active for this problem. The Diagnostic code for this problem will be active until the ECM is powered down.

Figure 1.3 - Typical Schematic (3512C Engine)

#Check the Status of the Start/Run/Stop Switch on Caterpillar ET

1). Open CAT ET and connect to the ECM. Read More: How to Connecting Caterpillar ET Software to the ECM.

2). Monitor the parameter for the Start/Run/Stop Switch on CAT ET. Read More: Status Tool on Caterpillar ET Software. The parameter for the switch reads "Stop" when the Start/Run/Stop Switch is turned to the STOP position. The parameter for the switch reads "Run" when the Start/Run/Stop Switch is turned to the RUN position (refer to Figure 1.1 above).

#3512B Well Service (Ignition Switch)

Figure 1.4 - Ignition Switch (Run)

Figure 1.5 - Ignition Switch (Stop)

#3500 OWS (Run/Stop Switch)

Figure 1.6 - Run/Stop Switch (Run)

Figure 1.7 - Run/Stop Switch (Stop)

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