CCU 523916.04 – Hydraulic Oil Filter Restriction Sensor Circuit Voltage Low

CCU 523916.04 (CCU )

Code: 523916.04



This fault code is generated when the voltage in the hydraulic oil filter restriction sensor circuit is lower than normal, indicating a possible short to ground or a fault within the sensor. This low voltage condition might lead the system to incorrectly assume that the filter is not restricted.


The control unit assumes that the filter is not restricted. If the last known state of the filter was restricted, the system commands a slow idle until the operator shuts off the engine to prevent damage.


  • Inspect Sensor and Wiring: Examine the hydraulic oil filter restriction sensor and its wiring for any signs of damage, wear, or short circuits. Repair or replace any defective parts.
  • Measure Voltage Levels: Use diagnostic tools to measure the voltage at the sensor to ensure it is within the specified range. Identify and address any deviations.
  • Replace Faulty Sensor: If the sensor is faulty, replace it to restore accurate pressure detection and system operation.
  • Ensure Proper Grounding: Verify that the sensor and its wiring are properly grounded to prevent low voltage conditions.
  • System Reset and Monitoring: After resolving the issue, reset the control unit and monitor the hydraulic system to confirm normal operation and that the fault code does not reappear.


Maintaining accurate voltage levels and sensor functionality is crucial for the reliable operation of the hydraulic system. Regular checks and maintenance of electrical components help prevent such issues and ensure consistent system performance.

Control Units: John Deere

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