CCU 002602.18 – Hydraulic Oil Level Low

CCU 002602.18 (CCU 2602.18)

Code: 002602.18

Shortcode: 2602.18


This fault code is issued when the hydraulic clean oil reservoir (COR) level switch detects a low oil level under specific conditions—specifically when the hydraulic oil temperature is low and the engine has been running for 2 to 10 seconds, depending on engine RPM. The low oil level indication often points to leakage from the secondary hydraulic circuit (SCV/Hitch) or the inlet lines to the piston, steering, or charge pumps. This situation could also involve a failed charge pump during vehicle operation. If associated codes (CCU 002602.18, HCU 002602.18, and SCC 002602.18) are present and the hitch will not raise or lower, it’s likely that the hitch spool is stuck in the retract position or the surge relief valve is stuck open, causing oil from the clean oil reservoir to drain into the sump.


The functionality of the hydraulic system is degraded due to the low oil level, which compromises the system’s ability to maintain pressure and perform operations efficiently.


  • Immediate Oil Level Inspection: Check and refill the hydraulic oil to the recommended level to ensure proper system operation.
  • Leak Detection and Repair: Conduct a thorough inspection of the hydraulic circuits, particularly the SCV/Hitch and inlet lines to the pumps, to identify and repair any leaks.
  • Check Charge Pump: Evaluate the condition and operation of the charge pump, replacing it if failure is detected.
  • Inspect Hitch Spool and Surge Relief Valve: If other related fault codes are present, examine the hitch spool and surge relief valve for any signs of being stuck and repair as necessary.
  • System Testing: After repairs, perform comprehensive testing of the hydraulic system to ensure all components function correctly and the oil level remains stable.


Regular monitoring and maintenance of the hydraulic system, including oil levels and leak checks, are crucial to prevent operational disruptions and ensure system longevity.

Control Units: John Deere

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