PIPE 0878504 - Caterpillar

Illustration 1 g02038433
Connections of the "Boom Angle" potentiometer This diagnostic code is associated with the "Boom Angle" potentiometer. The FMI 03 diagnostic code means that the Machine ECM has determined that the signal voltage of the potentiometer is above normal.The possible causes of this diagnostic code are listed below:
The power supply circuit for the sensor is open.
The return circuit is open.
The signal circuit is open or the sensor is disconnected.
The signal circuit is shorted to the sensor power supply.
The sensor has failed.
The ECM has failed. This situation is unlikely.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 of the connections in the circuit are clean and that all connections are secure. 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 these diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 2425 FMI 03 is active before performing this procedure.Note: Use a digital multimeter for the measurements in this procedure.Test Step 1. CHECK THE VOLTAGE AT THE SENSOR
The disconnect switch and the key start switch remain in the ON position.
At the machine harness connector for the sensor, measure the voltage between contact A (wire 159-BU) and contact B (wire 235-BK).Expected Result:The voltage measurement is 24 1.0 DCV.Results:
OK - The voltage measurement is 24 1.0 DCV. Proceed to Test Step 2.
NOT OK - The voltage measurement is not 24 1.0 DCV. Repair: There may be an open in the machine harness. Check the fuse for this circuit. Ensure that the fuse is not open. If the fuse is open, replace the fuse. Clear all diagnostic codes. Check if the diagnostic code is still active.If the code remains active, there is an open in the supply circuit of the machine harness. Repair the machine harness or replace the machine harness.STOPTest Step 2. CHECK FOR AN OPEN IN THE SIGNAL CIRCUIT
The key start switch and the disconnect switch remain in the ON position.
At the machine harness connector for the sensor, measure the voltage from signal contact C (wire J853-BU) to ground contact A (wire 159-BU).
Locate the bracket on the boom that contains the potentiometer. Remove the potentiometer from the bracket. After the potentiometer has been removed, slowly adjust the angle of the potentiometer to around 90 degrees. Observe the change in voltage output of the potentiometer as the angle of the potentiometer is adjusted.Expected Result:If the signal circuit for the sensor is correct, the pull-up voltage of the ECM should be indicated on the voltage measurement. The value of this voltage will vary as the angle is adjusted. The presence of a voltage will indicate that the signal circuit is NOT open. The total absence of a voltage during this