Robot stops and reports E4; wheels may not move or robot struggles to drive.

Safety first: Switch off the robot and remove it from the dock. Place it upside down on a table.

Clear wheel obstructions:

• Inspect both left and right drive wheels. Pull the wheels up and down to check suspension movement.
• Look for hair, strings, or carpet fibers wrapped around the wheel axles. Use tweezers or scissors to remove them.
• Check for small objects (toys, stones) lodged in the wheel wells or between the wheel and chassis.

Test wheel movement:

• Rotate each wheel by hand. They should turn smoothly with some resistance from the gearbox but no grinding or binding.
• If one wheel is significantly stiffer or makes grinding noises, its gearbox may be damaged.

After cleaning: Power the robot back on and start a short cleaning run on a flat, hard floor. If E4 no longer appears, the issue was likely debris.

If E4 returns: The affected drive wheel motor assembly may need replacement. Because the drive module is usually integrated (motor + gearbox + encoder), replacing the entire wheel module is recommended. If you are not experienced with disassembly and wiring, contact a professional.