Robot vacuum shows E4 and stops near obstacles, often after bumping into furniture

Safety first: Power OFF the robot and remove it from the dock.

• 1. Check bumper movement: Gently press the front bumper in and release it across its full width. It should move freely and spring back without sticking.
• 2. Remove debris: Inspect the gap between the bumper and the robot body. Use compressed air or a soft brush to remove dust, pet hair, and small objects that may be wedged inside.
• 3. Clean bumper sensors: Many Trifo models use infrared sensors behind small windows in the bumper. Wipe these windows with a soft, dry microfiber cloth. Do not use harsh chemicals.
• 4. Inspect for damage: If the bumper is visibly bent, cracked, or misaligned (for example after a drop), it may not actuate the internal switches correctly and may need replacement.
• 5. Internal check (optional): If comfortable, remove the top or bottom cover to access the bumper switch board. Ensure the bumper switch harness is firmly connected to the main board and that the micro-switches click when the bumper is pressed.
• 6. Reassemble and test: Reassemble the robot, power it ON, and start a cleaning cycle. Gently tap the bumper to confirm it responds normally.

Warning: Opening the robot may void warranty. If the bumper is physically broken or the E4 error persists after cleaning, contact Trifo support or a professional technician for bumper sensor module replacement.