John Deere 00 – HCU: Active Header Height Control Fault

The fault code '00' is a generic indicator of an issue within the Active Header Height Control (AHHC) system, which automatically adjusts the header's height and contour relative to the ground. This code signifies that a condition is preventing the system from operating as commanded, but it does not point to a specific component failure. The underlying cause could range from a simple calibration issue to a failure in the electrical or hydraulic components.

• 9540 WTS
• 9560 WTS
• 9580 WTS
• 9640 WTS
• 9660 WTS
• 9680 WTS
• 9560 STS
• 9650 STS
• 9660 STS
• 9750 STS
• 9760 STS
• 9860 STS
• S-Series
• 9450
• 9550
• 600FD
• 700FD
• 900-series bean heads

1. 1

   Check for specific Diagnostic Trouble Codes (DTCs) in the Header Control Unit (E01) via the corner post display to isolate the fault

2. 2

   Inspect the wiring harness between the combine and header for damage, corrosion, or loose connections

3. 3

   Check header height sensors and linkages for physical damage, binding, or obstructions (ensure float arm lock-out brackets are removed on 600FD platforms)

4. 4

   Verify that the Active Header Height Control is enabled on the corner post display

5. 5

   Check sensor voltages through the diagnostic addresses (should be within 0.5 to 4.5 volts, ideally set between 0.9 and 4.1 volts)

6. 6

   Check for blown fuses that could disable the entire AHHC system

7. 7

   Observe manual operation using the multifunction handle to verify basic hydraulic functions and valve power supply are intact

1. 1

   Address specific DTCs

   If any specific DTCs were found during the diagnostic check (e.g., sensor voltage too high/low), address those specific sensor or wiring issues first.

2. 2

   Perform header calibration

   Initiate calibration mode on the corner post display on a level surface. Lower the header completely to establish the minimum setting, then raise it completely for the maximum setting, and save the values.

3. 3

   Inspect and test sensors

   With the key on, manually move the sensor's linkage and monitor its voltage on the display. If voltage doesn't change smoothly between 0.5 and 4.5 volts, inspect wiring for continuity/shorts. Replace the sensor if wiring is intact.

4. 4

   Inspect and test control modules

   If sensors, wiring, and calibration are good, check for power and ground at the HCU connector. A defective Active Header Control card may require replacement by a dealer.

5. 5

   Check hydraulic system

   Ensure the drop rate is adjusted correctly per the operator's manual. On HydraFlex systems, check for incorrect accumulator settings that can cause the system to cycle or hunt.