SWITCH (Air Pressure) 7K0187 - Caterpillar

Illustration 1 g03299316
Connections of the Right Joystick Left/Right Position SensorThis diagnostic code is associated with the Right Joystick Left/Right Position Sensor. The ECM reads the input signal and the voltage of the signal is below normal. The sensor is located in the right joystick.The Right Joystick Left/Right Position Sensor receives power from the 10V power supply of the Implement ECM. The sensor is internally connected to the ground from the 10V sensor return for the Implement ECM. The illustration above indicates the power and ground connections for the position sensor.The position sensor is a PWM sensor that operates at a frequency of approximately 500 100 Hz. The position sensor sends a PWM input signal to the ECM. The duty cycle of the signal will vary from 7% to 93%. The variations in the duty cycle of the signal follow:
Table 1
Joystick Position     Acceptable Sensor PWM Duty Cycle (Percent)    
Full Forward / Full Right     7 to 14    
Centered     45 to 55    
Full Rearward / Full Left     85 to 93    The possible conditions that could cause this diagnostic code are:
The signal circuit is shorted to ground.
The sensor has failed.
The ECM has failed. This condition is unlikely. Note: If a CID 1482 diagnostic code for the 10V power supply has been activated, investigate and fix the problem before proceeding with this procedure.Note: Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, that all connections are secure and that all connections are 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.
Disconnect the machine harness connector C2 from the right joystick. Observe the status of the active CID 2477 FMI 04 diagnostic code.Expected Result:The status of the CID 2477 FMI 04 diagnostic code did not change when the connector for the joystick was disconnected. A CID 2477 FMI 03 diagnostic code has not been activated by the ECM. The CID 2477 FMI 04 diagnostic code remains active when the connector for the joystick is disconnected.Results:
OK - The CID 2477 FMI 04 diagnostic code remains active when the connector for the joystick is disconnected. The sensor is not the cause of the problem. Proceed to Test Step 2.
NOT OK - The CID 2477 FMI 04 diagnostic code is no longer active when the connector for the joystick is disconnected. A CID 2477 FMI 03 diagnostic code is activated by the ECM when the connector for the joystick is disconnected. The machine harness and the ECM are operating correctly.Repair: The