VARISTOR 2414662 - Caterpillar

Illustration 1 g01948293
Schematic of the pressure sensor (left rear parking brake oil)
This diagnostic code is associated with the pressure sensor (left rear parking brake oil). The FMI 08 diagnostic code means that the ECM has determined that the signal frequency or the signal pulse width is not within the expected range. The pressure sensors are PWM sensors. A 0% duty cycle represents 0 kPa (0 psi). A 100% duty cycle represents 5871 kPa (851 psi). The ECM measures the duty cycle of the signal. The possible causes of this diagnostic code are listed below:
The sensor has failed.
Intermittent connections or poor connections
Mechanical devices are loose.
The ECM has failed. This 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 1225 FMI 08 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 FOR POWER AT THE SENSOR.
Do not disconnect the harness connector from the sensor.
At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along the voltage supply wire (contact A).
Turn the key start switch and the disconnect switch to the ON position.
Measure the voltage from contact A 113-OR(Orange) to a ground location at the frame. Expected Result:The voltage is 24 DCV.Results:
OK - The voltage is 24 DCV. Proceed to Test Step 2.
NOT OK - The voltage is not 24 DCV. The circuit is open. Repair: Repair the machine harness or replace the machine harness.STOPTest Step 2. CHECK THE SIGNAL CIRCUIT OF THE SENSOR.
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 A and insert the probe along contact C H428-BK(Black), the signal wire.
At the back of the harness connector for the sensor, insert the 7X-1710 Multimeter Probe along contact B wire J765-BU(Blue) (ground wire).
Turn the disconnect switch and the key start switch to the ON position.
Monitor the signal of the sensor with the 146-4080 Digital Multimeter.
Without disconnecting the sensor or the hardware that is associated with the sensor from the machine, take the sensor through the full operating range of the sensor. Note: On some machines, it may be necessary to start the engine in order to take the sensor through the full operating range of the sensor.Expected Result:The sensor's signal responds in the manner that is described at the begining of this procedure.Results:
OK - The sensor's signal responds correctly. The sensor is operating correctly. Proceed to Test Step 3.
NOT OK - The