Robot vacuum displays E7 and will not charge or start a cleaning cycle.

Safety first: Turn off the robot and unplug the charging base from the wall before inspecting power components.

• Check charging contacts: Clean the robot's charging pads and the dock's contacts with a dry cloth to remove oxidation or dust.
• Verify dock power: Plug the dock into a known-good outlet and confirm the dock indicator light is on.
• Seat robot on dock: Place the robot firmly on the dock, ensuring the contacts align. Allow it to charge for at least 3 hours.
• Inspect battery (if accessible): Remove the battery cover on the underside, check for swelling, corrosion, or loose connectors. Do not puncture or crush the battery.
• If E7 remains after full charge: Replace the rechargeable battery pack with a compatible Bissell battery. If a new battery does not resolve the issue, the power management / main control board may need replacement.