ELBOW 3S1446 - Caterpillar

Illustration 1 g02434816
(1) Lift Cylinder Rod End Pressure Sensor located on the left side of the Implement Control Valve. View: Non-engine end frame access cover removed, on the left side of the Implement Control valve
Illustration 2 g02434818
Connections of the Lift Cylinder Rod End (RE) Pressure Sensor
This code is recorded when the ECM reads the input signal from the Lift Cylinder Rod End Pressure Sensor and the voltage is below normal. The position sensor is located on the left side of the Implement Control Valve.The Lift Cylinder Rod End Pressure Sensor receives power from the 8V power supply of the Implement ECM. The sensor is internally connected to the ground from the 8V sensor return of the Implement ECM. The illustration above indicates the power and ground connections for the pressure sensor.The sensor is a 50 MPa (7252 psi) rated pressure sensor that operates at approximately 500 Hz. The pressure sensor sends a PWM input signal to the ECM. The duty cycle of the signal will vary from 5% to 95%.If the PWM duty cycle or voltage of a sensor input circuit is less than 3%, an FMI 04 diagnostic code will be activated.The following table indicates the sensor PWM duty cycles at the given oil pressures.
Table 1
Lift Cylinder RE Pressure Sensor PWM Duty Cycle versus Pressure
Pressure Duty Cycle (Percent) Pressure Duty Cycle (Percent)
0 mpa (0 psi) 5 25.6 mpa (4000 psi) 51
13.8 mpa (2000 psi) 30 31.0 mpa (4500 psi) 61
17.2 mpa (2500 psi) 36 34.5 mpa (5000 psi) 67
20.7 mpa (3000 psi) 42 37.9 mpa (5500 psi) 73
24.1 mpa (3500 psi) 48 50 mpa (7252 psi) 95 The possible causes of this diagnostic code are listed:
The signal circuit is shorted to ground.
The sensor has failed.
The ECM has failed. This condition is unlikely. Note: If a CID 0041 diagnostic code for the 8V power supply has been activated, correct 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. Inspect the connections for the following:
Connections are clean.
Connections are secure.
Connections are in good condition.Note: 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 from the pressure sensor. Observe the status of the active CID 0769 FMI 04 diagnostic code. Expected Result:The status of the CID 0769 FMI 04 diagnostic code did not change when the pressure sensor was disconnected. A CID 0769 FMI 03 diagnostic code has not been activated by the ECM. The CID 0769 FMI 04 diagnostic code