E9
Hecht Bumper / Collision Sensor Fault

Robot mower shows E9 and refuses to start; often after impact or collision.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Front bumper stuck in pressed position, Broken bumper spring or bracket, Dirt or grass blocking bumper movement, Faulty bumper switch or sensor cable

How to Fix / Troubleshooting

Safety first: Turn OFF the main power before inspecting the bumper.

  • Check bumper movement: Press the front bumper in and release it. It should move freely and return to its original position. If it sticks, clean around the edges.
  • Remove debris: Look for packed grass, mud, or stones between the bumper and chassis. Clean with a brush and damp cloth.
  • Inspect for damage: Check for cracks or bent plastic that prevent proper movement. Replace the Front Bumper Assembly if damaged.
  • Reset error: After cleaning, power OFF for 30 seconds, then ON, and try to start a manual mow.
  • If E9 persists: The internal Bumper Switch or wiring harness may be faulty. A technician should open the housing, test the switch with a multimeter, and replace if necessary.
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Repair Difficulty

Medium 3/5

Required Part

Front Bumper Assembly
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