RING-RETAINING 2143886 - Caterpillar

Illustration 1 g02035733
Schematic of the "Right Joystick Thumbwheel Modulation" control
This diagnostic code is associated with the "Right Joystick Thumbwheel Modulation" control. An FMI 08 diagnostic code means the Machine ECM has found the signal frequency or the pulse width not within the expected range.The "Thumbwheel Modulation" control has an output frequency of approximately 500 Hz. The duty cycle of the signal changes as the "Thumbwheel" position is changed. The duty cycle varies from approximately 19% at the minimum position to approximately 77% at the maximum position. The duty cycle is approximately 48% at the center position.The possible causes of this diagnostic code are listed below:
The "Thumbwheel Modulation" control has failed.
Intermittent connections or poor connections
Mechanical devices are loose.
The Machine ECM may have failed, but is unlikely.System Response:When this diagnostic code occurs, there is no warning on the monitor. The function for the work tool that is controlled by the "Thumbwheel Modulation" control will not function.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 1658 FMI 08 diagnostic code is active before performing this procedure.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure. Test Step 1. CHECK FOR POWER AT THE "THUMBWHEEL MODULATION" CONTROL.
Do not disconnect the harness connector from the joystick.
Turn the key start switch and the disconnect switch to the ON position.
At the back of the harness connector for the joystick, insert a 7X-1710 Multimeter Probe along the voltage supply wire J850-WH(White) (contact 1).
Measure the voltage from contact 1 (wire J850-WH(White)) to frame ground. Expected Result:The voltage is approximately 8 DCV.Results:
OK - The voltage is approximately 8 DCV. Proceed to Test Step 2.
NOT OK - The voltage is not approximately 8 DCV. The circuit is open. Repair: Repair the machine harness or replace the machine harness.STOPTest Step 2. CHECK THE SIGNAL CIRCUIT OF THE "THUMBWHEEL MODULATION" CONTROL FOR THE CORRECT DUTY CYCLE.
Turn the key start switch and the disconnect switch to the OFF position.
At the back of the harness connector for the sensor, remove the 7X-1710 Multimeter Probe from contact 1 (wire J850-WH(White)) and insert the probe along the signal wire E473-GY(Grey) (contact 3).
At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along the ground wire 235-BK(Black) (contact 2).
Turn the disconnect switch and the key start switch to the ON position.
Monitor the duty cycle of the "Thumbwheel Modulation" control with the 146-4080 Digital Multimeter.
Without disconnecting the joystick or the hardware that is associated with the joystick from the machine, move the "Thumbwheel" through the entire range of motion. Note: On some machines, starting the engine may be necessary, to move the Thumbwheel through the entire range of motion.Expected Result:The value of the "Thumbwheel" duty cycle responds as described at the start of this procedure.Results:
OK - The value of the "Thumbwheel" duty cycle responds correctly. The "Thumbwheel Modulation" control is