FILM-INFORMATION 1553593 - Caterpillar

Illustration 1 g01950164
(1) Retaining cable
(2) Retaining pin
Illustration 2 g01731828
Schematic of the pressure sensor (differential oil)
This diagnostic code is associated with the pressure sensor (differential oil). The FMI 02 diagnostic code means that the Brake ECM has determined that the signal of the position sensor is erratic or intermittent. Refer to Systems Operation, "Sensors" for information regarding the operation of the sensor and the location.The pressure sensors are PWM sensors. A 0% duty cycle represents 0 kPa (0 psi). A 100% duty cycle represents 3163 kPa (459 psi). The ECM measures the duty cycle of the signal.The possible causes of this diagnostic code are listed below:
The connection of the signal circuit for the sensor is intermittent.
The signal circuit for the sensor is shorted to the +battery circuit.
The sensor has failed.
The power circuit or the ground circuit has failed.
The ECM has failed. A failure of the ECM is unlikely.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 0766 FMI 02 is active before performing this procedure.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.
When it is necessary to work under the machine with the body (bed) raised, attach the body (bed) retaining cables to the rear tow points. Install the rear tow point pins through the ends of the retaining cables.Failure to properly secure the body (bed) may result in personal injury or death.
Test Step 1. CHECK THE VOLTAGE AT THE SENSOR.
Disconnect the harness connector from the sensor.
Turn the key start switch and the disconnect switch to the ON position.
At the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along the voltage supply wire (contact A).
Measure the voltage from contact A (wire 113-OR(Orange)) to contact B (wire J765-BU(Blue)).Expected Result:The voltage is 24 VDC.Results:
OK - The voltage is 24 VDC. Proceed to Test Step 2.
NOT OK - The voltage is not 24 VDC. The + battery circuit in the machine harness has failed.Repair: Replace the machine harness or repair the machine harness.STOPTest Step 2. CHECK THE SIGNAL CIRCUIT AT THE SENSOR.
Connect the machine harness to the sensor.
Disconnect the J1 and J2 connectors from the Brake ECM.
Turn the key start switch and the disconnect switch to the OFF position.
Remove the 7X-1710 Multimeter Probe from the voltage supply wire (contact A).
At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along the ground wire (contact C).
Measure the voltage from contact C (wire C473-GN(Green)) to all the connections of the J1 and J2 connectors.Expected Result:The resistance is greater than 5000 ohms.Results:
OK - The resistance is greater than 5000 ohms. The signal circuit is correct. Proceed to Test Step 3.
NOT OK - The resistance is less than 5000 ohms. The ground circuit in the machine harness has failed.Repair: Replace the machine harness or repair the machine harness.STOPTest Step 3. CHECK THE WIRING HARNESS OF THE SENSOR FOR