NAC Robot Lawnmowers Error Codes

E01

Robot lawnmower will not start mowing; display shows E01 immediately after power‑on.

Emergency Stop / Stop Button Active

E02

Robot lawnmower does not detect the boundary wire and attempts to leave the mowing area; display shows E02 Boundary Error.

Boundary Loop Signal Not Detected

E03

Robot lawnmower stops shortly after starting and displays E03 Lifted / Tilted error even when on level ground.

Lift / Tilt Sensor Fault

E04

Robot lawnmower stops and displays E04 Blade Blocked; cutting disc does not rotate.

Blade Motor Overload / Stall

E05

Robot lawnmower displays E05 Wheel Blocked; one or both drive wheels do not turn.

Drive Wheel Motor Overload / Stall

E06

Robot lawnmower shows E06 No Loop Signal when approaching the boundary; mower stops and will not continue.

Weak or Distorted Boundary Signal

E07

Robot lawnmower displays E07 No Charge; mower cannot charge when docked on the NAC charging station.

Charging Circuit Failure

E08

Robot lawnmower shows E08 Battery Error; runtime is very short or mower shuts down unexpectedly.

Battery Pack Fault / Capacity Loss

E09

Robot lawnmower displays E09 Motor Overheat; mower stops and will not resume until cooled.

Drive or Blade Motor Overheating

E10

Robot lawnmower shows E10 Sensor Error; mower behaves erratically near boundary and obstacles.

Front Collision / Bumper Sensor Fault

E11

Robot lawnmower displays E11 Wheel Encoder Error; mower drives in circles or cannot navigate straight lines.

Wheel Speed Sensor / Encoder Failure

E12

Robot lawnmower shows E12 Cutting Height Error; mower cannot adjust cutting height or gets stuck when changing height.

Cutting Height Motor / Mechanism Jam

E13

Robot lawnmower displays E13 Rain Sensor Error; mower refuses to start even in dry weather or ignores rain.

Rain Sensor Circuit Fault

E14

Robot lawnmower shows E14 PIN Error; mower locked and will not start mowing.

Security PIN / Keypad Fault

E15

Robot lawnmower displays E15 GPS Error (on GPS‑equipped NAC models); mower cannot start navigation or returns to base immediately.

GPS Module Communication Failure

E16

Robot lawnmower shows E16 Ultrasonic Sensor Error (on models with obstacle sonar); mower fails to detect obstacles or stops with error.

Ultrasonic Obstacle Sensor Fault

E17

Robot lawnmower displays E17 IMU Error; mower cannot maintain straight path and error appears after startup self‑test.

Inertial Measurement Unit (IMU) / Gyro Fault

E18

Robot lawnmower shows E18 Communication Error; display may freeze or mower does not respond to commands.

Main Board to Control Panel Communication Failure

E19

Robot lawnmower displays E19 Overcurrent Error; mower stops abruptly when starting blade or climbing slope.

Excessive Current Draw on Motor Circuit

E20

Robot lawnmower shows E20 Docking Error; mower cannot align with or stay in the NAC charging station.

Docking Alignment / Guide Signal Fault

Symptom

Robot lawnmower base station LED indicates a fault (blinking or red) but the mower shows no specific error code.

Charging Station Internal Fault

Symptom

Robot lawnmower cannot be detected or controlled via the NAC mobile app or wireless connection.

Wireless Connectivity Failure

Symptom

Robot lawnmower does not leave the charging station at the scheduled time.

Scheduling / Start Inhibition

Symptom

Robot lawnmower does not respond to the stop button immediately; there is a noticeable delay before it stops.

Delayed Emergency Stop Response

Symptom

Robot lawnmower emits a burning smell or shows signs of melted plastic near the blade motor area.

Blade Motor Overheating / Insulation Failure

Symptom

Robot lawnmower fails to detect obstacles and collides hard with trees or walls, even though it has a bumper.

Bumper Mechanical Failure (No Error Code)

Symptom

Robot lawnmower frequently gets stuck on small bumps, roots, or transitions between lawn and paths.

Ground Clearance / Traction Issue

Symptom

Robot lawnmower is very noisy during operation, with grinding or rattling sounds from underneath.

Mechanical Noise / Bearing Wear

Symptom

Robot lawnmower leaves clumps of grass and the cut looks ragged, especially in damp conditions.

Poor Cut Quality

Symptom

Robot lawnmower leaves uncut strips of grass and misses areas within the boundary.

Inefficient Mowing Pattern / Coverage Issue

Symptom

Robot lawnmower occasionally fails to detect the boundary and crosses outside the mowing area without showing an error code.

Marginal Boundary Detection

Symptom

Robot lawnmower occasionally reboots by itself while mowing; the display restarts and mowing resumes or stops.

Unexpected System Reset

Symptom

Robot lawnmower occasionally shuts down in the middle of the lawn with no error message on the display.

Intermittent Power Loss

Symptom

Robot lawnmower occasionally spins its wheels without moving forward, especially on slopes or wet grass.

Loss of Traction

Symptom

Robot lawnmower runs for only a short time (e.g., 10–20 minutes) before returning to the base without an error code.

Reduced Battery Capacity / Early Return

Symptom

Robot lawnmower shows condensation or moisture inside the display window after rain.

Water Ingress / Seal Failure

Symptom

Robot lawnmower veers to one side and cannot drive straight, even on level ground.

Drive Imbalance / Traction Difference

Symptom

Robot lawnmower vibrates excessively, especially when the blade starts or stops.

Imbalanced Cutting System