John Deere 521421.19 – HCC (Hitch Control Center): Rear Hitch Encoder Lower Fault / Rear Hitch Encoder Increase Fault

The control module detects an erratic, out-of-range, or missing signal from the rear hitch position encoder (sensor) while the hitch is being commanded to move, preventing the system from accurately determining the physical position of the rear hitch arms.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8245R
• 8270R
• 8295R
• 8320R
• 8345R
• 8370R
• 8400R
• 9470RT
• 9520RT
• 9570RT

1. 1

   Inspect the wiring harness and connector at the Rear Hitch Position Sensor (Encoder) for corrosion, backed-out pins, or physical damage from debris.

2. 2

   Back-probe the sensor to check the signal voltage. Voltage should read between 0.5V – 2.0V at the transport lock (fully raised) and 3.0V – 4.5V when fully lowered. If voltage is stuck, erratic, or drops out, the sensor is internally faulty.

3. 3

   Look for accompanying codes such as HCC 521421.31 (Encoder Lower Data Fault) or HCC 001873.04 (Position Sensor Circuit Voltage Low) to further isolate the sensor circuit.

4. 4

   Attempt to run a rear hitch calibration before replacing parts, as a loss of calibration can cause erratic encoder faults.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery ground to prevent shorting the 5V reference circuit.

2. 2

   Remove the Sensor

   Locate the rear hitch position encoder on the rear rockshaft/hitch assembly. Disconnect the electrical harness and unbolt the sensor linkage.

3. 3

   Install the New Sensor

   Mount the new position sensor and attach the mechanical linkage. Reconnect the wiring harness.

4. 4

   Perform Hitch Calibration

   You must perform a Rear Hitch Calibration using the tractor's CommandCenter display or John Deere Service ADVISOR. The HCC will not recognize the new sensor's travel limits until this is completed.

5. 5

   Clear Codes and Test

   Clear the 521421.19 code from the HCC module. Cycle the rear hitch fully up and down several times to verify smooth operation and ensure the code does not return.