Roborock Error 4 — Cliff sensor error
DIRECT ANSWER
COMMON CAUSES · RANKED
Dusty cliff sensors MOST COMMON
A film of dust over the sensor windows under the front edge makes the floor invisible to the robot. Wiping them is the whole of Roborock's first instruction.
Robot over a raised edge
Parked half over a stair or ledge, the sensors correctly see a drop and stop everything.
Dark or shag carpet
Roborock's own FAQ says dark carpet "triggers the cliff sensors in the same way as a drop", and long shag fibres do the same. The infrared beam never comes back, so the robot believes it is at an edge.
A faulty sensor RARE
If the windows are clean, the floor is light and the robot sits on open ground, one of the sensors is reading wrong. Roborock's article ends there: contact support.
HOW TO FIX IT
Wipe all cliff sensors
Flip the robot and wipe every sensor window along the front underside with a soft dry cloth. Roborock's fix starts and nearly ends here.
Move away from drops and dark rugs
Set the robot down at least a metre from stairs or ledges and off any dark or shag carpet, which is the second half of Roborock's instruction, then restart.
Fence the rug with a no-go zone
If the error only fires on one black or shag rug, draw a no-go zone over it in the app. Roborock confirms the sensors cannot be switched off, so avoidance is the only setting you have.
Power cycle and retest on light floor
Hold the power button until the robot switches off, turn it back on and start a short clean on light hard floor. An error that survives this on clean sensors is a sensor fault.
IF IT STILL FAILS
WHEN TO STOP
Do not try to blind the cliff sensors to get past a dark rug. Roborock says they cannot be disabled because they are what keeps the robot off the stairs, so anything that covers them removes that protection for the whole house. A sensor that fails on a clean, light, open floor is a warranty case: support@roborock.com or 1-855-960-4321 (US, 24/7) inside the first year.
RELATED FIRMWARE
S5 series (S5)
SAMPLE DATA — dataset in progressFirmware timelines are rebuilt monthly from release notes. Versions marked as sample data are community-reported and not yet verified. Full firmware timeline →
MODELS AFFECTED
| Model | Status | Firmware | Parts | Verified |
|---|---|---|---|---|
| Roborock S5 | limited | s5 | Parts → | 2026-07-05 · Source |
| Roborock S5 Max Roborock's FAQ states the cliff sensors cannot be disabled on any of these models because they keep the robot off stairs, so a dark rug is handled with a no-go zone rather than a setting. · Source | limited | s5 | Parts → | 2026-07-05 · Source |
| Roborock S6 | limited | s6 | Parts → | 2026-07-05 · Source |
| Roborock S6 MaxV | limited | s6 | Parts → | 2026-07-05 · Source |
| Roborock S7 | active | s7 | Parts → | 2026-07-05 · Source |
| Roborock S7 MaxV | active | s7 | Parts → | 2026-07-05 · Source |
| Roborock S8 | active | s8 | Parts → | 2026-07-05 · Source |
| Roborock S8 Pro Ultra | active | s8 | Parts → | 2026-07-05 · Source |
| Roborock Q5 / Q7 | active | q | Parts → | 2026-07-05 · Source |
Models resolved from the series chips above. Support status comes from our EOL library; rows link to the matching parts and firmware pages.
FIELD NOTES
The official Error 4 fix is one line: wipe the cliff sensors and keep the robot off dark or shag carpet. Two other Roborock FAQ entries say the quiet part out loud. Dark carpet "triggers the cliff sensors in the same way as a drop", long shag fibres do the same, and "it is not possible to disable cliff sensors as they are essential in most homes". Roborock even asks owners to "understand and forgive this drawback".
So for a dark rug there is no setting to change on these models. The choices are a no-go zone around the rug, lifting the rug during runs, or accepting that the robot skips it. That is worth knowing before you spend an evening cleaning sensors that were never dirty.
The dust case is real too, and it creeps up. The sensor windows sit under the front edge where fine dust settles, so a monthly wipe with a dry cloth belongs on the maintenance list next to the brush and filter. And when Error 4 turns up with Error 3 or a trapped alert, the robot is physically over an edge; fix the position first and the sensors will agree with you.
FAQ · REAL QUESTIONS
What does Roborock error 4 mean?
Error 4 is a cliff sensor error: the downward sensors under the front edge report a drop the robot cannot make sense of. Dust on the windows, a real ledge, or dark and shag carpet are the causes Roborock names. Wipe the sensors, move the robot, restart.
How do I reset the cliff sensor error on a Roborock?
There is no reset menu for it. Wipe every sensor window with a dry cloth, set the robot on light, level floor away from stairs, hold the power button until it switches off, then power on and start a short clean. If it fires again on clean sensors, the sensor itself is faulty.
Why does my Roborock get error 4 on dark carpet?
Because the cliff sensors measure infrared light bouncing back from the floor, and a dark or deep-pile surface swallows it. Roborock's FAQ says dark carpet triggers the sensors "in the same way as a drop" and that they cannot be disabled. Use a no-go zone.
Can I turn off the cliff sensors on a Roborock?
No. Roborock states it is "not possible to disable cliff sensors as they are essential in most homes". They are the only thing stopping the robot at the top of a staircase, so the workaround for a dark rug is a no-go zone, not a setting.
Sources
- Roborock Support — What should I do when error 4 occurs?
- Roborock Support — Why does the robot cleaner refuse to clean the dark carpet?
- Roborock Support — Why does the robot cleaner refuse to clean the shag carpet?
- Roborock Support — What should I do when error 8 occurs? (robot trapped)
- Roborock S5 Max user manual — Troubleshooting
- Roborock US — Service and warranty
Corrections
Spotted an error? Report a correction — fixes ship within 48h and are logged on this page.