Robot vacuum reports E4 and stops, often turning in circles or failing to move straight.

Safety first: Turn the robot OFF and remove it from the dock. Place it upside down on a towel.

Inspect the right wheel:

• Pull the right drive wheel down and rotate it by hand. Remove any hair, string, or fibers wrapped around the axle or trapped in the wheel well.
• Use tweezers and small scissors carefully to avoid cutting rubber treads.
• Vacuum out dust and debris from the wheel cavity.

Check for smooth rotation:

• Both wheels should rotate with similar resistance. If the right wheel feels rough, grinds, or locks, the gearbox or motor may be damaged.

Reset and test:

• Power cycle the robot using the main switch.
• Start a cleaning cycle on a flat surface and watch whether the right wheel turns properly.

Advanced repair: Persistent E4 usually indicates a failing right wheel module. Replacement requires opening the bottom cover, unplugging the right wheel harness from the mainboard, and installing a new right wheel assembly. If under warranty, contact Proscenic support rather than opening the unit yourself.