GEAR-CRANKSHAFT 9Y5215 - Caterpillar

System Operation Description:The air/fuel ratio control includes a fuel actuator. The fuel actuator is controlled by the ECM. Mechanical linkage connects the fuel actuator to the fuel valve. The ECM controls the position of the actuator in order to adjust the amount of fuel that enters the carburetor. Varying the flow of the fuel affects the air/fuel ratio.The ECM varies the current flow through the actuator's armature in order to position the actuator. The ECM sends the current in pulses. The current flow of the pulses is limited to a maximum of four amperes. The frequency of the pulses is determined by the load on the actuator.The ECM calibrates the fuel actuator during the power up sequence. When power is first applied to the ECM, the calibration runs for approximately fifteen seconds. The ECM performs these steps in order to calibrate the fuel actuator:
The ECM drives the actuator to the closed position for approximately three seconds.
The ECM smoothly drives the actuator to the fully open position.
The ECM holds the actuator at the full open position for approximately three seconds.
The ECM removes the command signal from the actuator. A spring that is inside the actuator returns the actuator to the closed position.The actuator provides a position feedback signal to the ECM. The ECM monitors the position feedback signal. If the position feedback signal does not equal the value that is expected by the ECM, a diagnostic code is generated.The ECM applies 5.7 VDC to the actuator for the position feedback signal.The ECM can generate the following diagnostic codes for the fuel actuator:576-02 Position Control Failure - The engine speed is greater than 700 rpm. The difference between the actual position of the actuator and the desired position of the actuator is greater than 15 percent of the actuator's maximum travel.577-11 Gain Fault - The calibration of the actuator has been completed. The full range of the actuator's travel is not within the specifications.578-11 Offset Fault - The calibration of the actuator has been completed. The minimum position of the actuator is not within the specifications.The ECM will not shut down the engine when a fault for the fuel actuator is detected. The engine will run. However, engine performance or emissions may be degraded.The most likely cause of a diagnostic code is a problem with the linkage. The next likely cause is a problem with the wiring. The next likely cause is a problem with the actuator. The least likely cause is a problem with the ECM.
Illustration 1 g01274209
Schematic diagram of the fuel actuatorThe engine is equipped with a remote control panel that includes a status control module and air/fuel ratio control.
Illustration 2 g01274210
Schematic diagram of the fuel actuatorThe engine is configured for Canadian Standards Association (CSA). The engine is equipped with an optional remote control panel with air/fuel ratio control.Test Step 1. Inspect the Electrical Connectors and the Wiring
Set the engine control to the OFF/RESET mode. Remove the electrical power from the engine.Note: For the following steps, refer to Troubleshooting, "Inspecting