HOSE AS 3587390 - Caterpillar

Illustration 1 g01401658
Speed Control Thumbwheel connectionsThis diagnostic code is associated with the Speed Control Thumbwheel Position Sensor. The Thumbwheel is located on the left Speed / Direction Handle. The FMI 04 diagnostic code is activated when the Machine ECM detects that the voltage of the thumbwheel position sensor PWM input signal is below normal.The position sensor is a PWM sensor that operates at a frequency of approximately 500 100 Hz. The sensor sends a 0.0 VDC to 5.0 VDC PWM signal to the ECM in order to indicate the position of the thumbwheel. The duty cycle of the signal will determine the amplitude of the voltage. A 20 percent duty cycle will result in a voltage of approximately 1.0 VDC on the signal circuit. An 80 percent duty cycle will result in a voltage of approximately 4.0 VDC. A 50 percent duty cycle will result in a voltage of approximately 2.5 VDC.When the Speed Control Thumbwheel is moved to the full left position in order to decrease the speed, the sensor PWM duty cycle input to the ECM is 20 5 percent. When the Speed Control Thumbwheel is moved to the full right position in order to increase the speed, the sensor PWM duty cycle input to the ECM is 80 5 percent. When the Speed Control Thumbwheel is in the center position, the sensor PWM duty cycle input to the ECM is approximately 50 percent.The possible causes of this diagnostic code are listed:
The signal circuit is shorted to a ground source.
The sensor has failed.
The ECM has failed. This failure is unlikely. This procedure should not require entry into any enclosures that contain hazardous voltage components and should not require any hazardous voltage connections to be disconnected.When an area that contains hazardous voltage components must be entered for a service procedure, the "Safe Shutdown Procedure for Electric Drive Tractors" procedure must be performed before any enclosures that contain hazardous voltage components are opened or before any hazardous voltage connectors are disconnected. Refer to the Troubleshooting, "Electrical Maintenance Guidelines" section of this manual. Perform the "Safe Shutdown Procedure for Electric Drive Tractors" procedure before any of the hazardous voltage areas are opened or before hazardous voltage connectors are disconnected.Note: Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure and in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure. Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the problem has been corrected.Test Step 1. CHECK THE SENSOR
Turn the disconnect switch and the key start switch to the ON position. DO NOT START THE ENGINE.
Disconnect the machine harness side of the handle connector from the Speed / Direction Handle. Observe the status of the active CID 1657 FMI 04 diagnostic code.Expected Result:The status of