PISTON 0000980 - Caterpillar

Illustration 1 g01003309
Schematic of the Position Sensor for the Service Brake Pedal
This diagnostic code is recorded when the ECM reads the duty cycle or the frequency of the sensor as being out of range.Note: This diagnostic code is usually an intermittent condition. The diagnostic code may be active or the diagnostic code may not be active.The output frequency of the position sensor is approximately 500 Hz. The duty cycle of the signal changes as the position sensor moves. The duty cycle varies from 25% when the pedal is depressed. The duty cycle varies to 42% when the pedal is released.The possible causes of this condition are listed:
The signal circuit is shorted to the + 8 V sensor supply or shorted to ground intermittently.
The signal circuit is open intermittently or the sensor is disconnected.
The sensor may have failed.Note: This procedure can cause new diagnostic codes to be recorded. Ignore these created diagnostic codes. When the procedure is completed, clear the created diagnostic codes.System Response:When this diagnostic code occurs, the action lamp is ON. The diagnostic code will cause the pedal to stop functioning. The diagnostic code will not affect any other machine operations.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 to frame ground.Expected Result:The voltage is 8 DCV.Results:
OK - The voltage is 8 DCV. Proceed to Test Step 3.
NOT OK - The voltage is NOT 8 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 the signal wire (contact C).
At the back of the harness connector for the sensor, insert the 7X-1710 Multimeter Probe along the ground wire (contact B).
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 to take the sensor through the full operating range of the sensor.Expected Result:The sensor signal responds in the manner that is described at the beginning of this procedure.Results:
OK - The sensor signal responds correctly. The sensor is operating correctly. Proceed to Test Step 3.
NOT OK - The sensor signal does not respond correctly. The sensor is NOT operating correctly.Repair: Replace the sensor.STOPTest Step 3. CHECK THE SIGNAL CIRCUIT AT THE ECM.
Turn the key start switch and the disconnect switch to