Roborock Error 15 — Wall Sensor Fault

What Does This Error Mean?

Error 15 means the wall sensor on the right side of the robot can't see properly.
It's almost always dust or pet hair on the small infrared window — wipe it clean with a dry microfibre cloth.
If the sensor is clean but Error 15 persists, the sensor module needs replacing or calibrating.

Affected Models

Roborock S7
Roborock S8
Roborock Q7 Max
Roborock S5 Max
Roborock S6 MaxV

Common Causes

Dust or pet hair on the wall sensor window (most common)
Sensor scratched from running into a hard surface
Sticker or label residue covering the sensor
Robot positioned against a black or very glossy surface that reflects poorly
Sensor module failed internally (uncommon)

How to Fix It

Find the wall sensor.

On most Roborock models, the wall sensor is a small clear window on the front-right side of the robot, near the side brush.
It's tiny — about the size of a pencil eraser — and easy to miss.
Refer to your model's manual if you're not sure.
Wipe it with a dry microfibre cloth.

Dust and pet hair stick to the IR window over time and degrade the signal.
Use a clean, dry microfibre cloth — no liquid cleaners.
Most Error 15 events clear after a 10-second wipe.
Check for sticker residue or scratches.

Inspect the window in good light.
Sticker glue from a removed label, a deep scratch from running into furniture, or any film over the window will degrade the sensor.
Sticker residue can be removed with isopropyl alcohol on a cotton bud — apply sparingly.
Restart and watch for the error.

Set the robot in the middle of a normal floor area and press Clean.
Error 15 should clear within 30 seconds of starting.
If it returns immediately, the sensor module itself is failing and needs Roborock service.

Frequently Asked Questions

What does the wall sensor do?

It's a short-range infrared sensor that helps the robot follow walls during edge cleaning.
Without it, the Roborock can still navigate using its main lidar or camera, but edge work — running close along walls — gets less precise.
The robot will still clean, just not as thoroughly along edges.

Can I keep using the robot with Error 15?

Yes, in most cases the robot will refuse to start a new cleaning cycle but will continue any cycle that's already running.
You'll lose precision along walls but the rest of the floor still gets cleaned.
Treat it as a soft warning — schedule a cleaning of the sensor and you're done.