For Roomba 600, 800/900 and 980, “Error 6: cliff sensor, dark floor or stair edge” is a distinct manufacturer-documented diagnostic intent. This page preserves the exact code or light pattern, groups every applicable catalog model and limits action to the official safe user check. iRobot's official material anchors this branch with the exact wording “Cliff Sensors are dirty”. That wording identifies the documented condition; it does not by itself prove that a battery, motor, board, sensor, dock or other replaceable component has failed. Keep “Error 6: cliff sensor, dark floor or stair edge” separate from every other alert on the same appliance. Match the full number, colour, flash order, spoken phrase or display text before acting; a different pattern owns a different diagnosis and may have a different stop condition. Power off and wipe every cliff sensor with a clean dry cloth. Move the robot away from the edge, make any rug flush with a stair edge, and use a Virtual Wall if the same dark area repeatedly triggers the warning. If the exact “Error 6: cliff sensor, dark floor or stair edge” condition clears and the appliance completes one normal start, charge or cleaning cycle, stop the test and monitor it. If it returns unchanged, do not repeat resets or infer a part: record the code, model and serial number for authorised iRobot support. Power the robot off and remove it from the dock before turning it over or touching a moving part. Keep charging contacts dry, use no metal probe and never open a battery pack or electronics housing.
Models covered
Safety first
- Power the robot off and remove it from the dock before turning it over or touching a moving part. Keep charging contacts dry, use no metal probe and never open a battery pack or electronics housing.
What the symptom may indicate
Checks in the right order
- Confirm the exact code or pattern
For Roomba 600, 800/900 and 980, “Error 6: cliff sensor, dark floor or stair edge” is a distinct manufacturer-documented diagnostic intent. This page preserves the exact code or light pattern, groups every applicable catalog model and limits action to the official safe user check.
- Make the appliance safe
Power the robot off and remove it from the dock before turning it over or touching a moving part. Keep charging contacts dry, use no metal probe and never open a battery pack or electronics housing.
- Perform the official user check
Power off and wipe every cliff sensor with a clean dry cloth. Move the robot away from the edge, make any rug flush with a stair edge, and use a Virtual Wall if the same dark area repeatedly triggers the warning.
- Retest once and decide
If the exact “Error 6: cliff sensor, dark floor or stair edge” condition clears and the appliance completes one normal start, charge or cleaning cycle, stop the test and monitor it. If it returns unchanged, do not repeat resets or infer a part: record the code, model and serial number for authorised iRobot support.
Stop and get qualified help when
- Stop immediately for liquid on the robot or dock, a swollen battery, burning smell, hot or discoloured contacts, damaged wiring, a fall risk, or the same alert after the single documented check. Use authorised service. If the exact “Error 6: cliff sensor, dark floor or stair edge” condition clears and the appliance completes one normal start, charge or cleaning cycle, stop the test and monitor it. If it returns unchanged, do not repeat resets or infer a part: record the code, model and serial number for authorised iRobot support.
Next step
Repair, replace a part, or arrange a diagnosis?
Use the checks and stop conditions above to choose a cautious next step. A symptom alone never proves that the appliance has failed.
Resolve it without buying anything
Complete the 4 user-accessible checks in order. If normal operation returns and no warning sign remains, no replacement is indicated.
Replace only the confirmed part
If the checks isolate a worn or blocked component, match its complete reference to the exact appliance model before ordering.
This guide does not identify a replacement part. Do not order a generic component from the symptom alone.
Arrange a diagnosis before replacing the appliance
Stop at any warning sign listed above. A qualified diagnosis should confirm that repair is unsafe, unavailable or uneconomical before an appliance replacement is considered.
Sources used
- iRobot — iRobot's official Error 6, Roomba 500–900 for Roomba 600, 800/900 and 980 states exactly: “Cliff Sensors are dirty” This short quotation is the source anchor for this intent.
Last checked: 30 August 2026