K1 Max Z-Homing Failure: PR_ERR_CODE_PRES_VAL_IS_CONSTANT (Error Key521)

Flagship K Series Creality Flagship K1 Max
1

When running the G28 (Home All) command, X and Y home successfully. The toolhead then moves to the center of the bed, but the Z-axis refuses to move upward. The homing sequence stops immediately and throws the following error:

{'code': 'key521', 'msg': 'PR_ERR_CODE_PRES_VAL_IS_CONSTANT: The pressure data for channel={0} is incorrect. The value is constant {1}.', 'values': [1]}

What I Have Already Checked:

  1. Toolhead Board Communication: The M105 command reads and returns normal temperatures for both the hotend and the heated bed, confirming the toolhead board is online and communicating.

  2. Physical / Nozzle Check: The nozzle is clean, free of plastic blobs, and not pressed against or bound to the build plate. There is no debris around the strain gauge load cells.

    Has anyone encountered this specific constant value error? Does this usually point to a loose/damaged strain gauge ribbon cable (FFC) or a complete failure of the strain sensor breakout board?
    Are there any console diagnostic commands in Klipper/Fluidd to pull live ADC or raw strain sensor (prtouch) readings to verify if channel 1 is completely unresponsive?

Any advice or steps to further isolate this issue would be greatly appreciated!