iRobot Roomba Combo j7+ keeps stopping, pulsing or shutting off

The checks in more detail

The common physical causes are simple. Tangled hair or string stops the brushes and the wheels, so turn the robot over and clear them. The cliff sensors on the underside can be dirty and make the robot believe it is at a drop, so wipe them with a dry cloth. Dark rugs can look like a cliff to some sensors, so use a keep-out zone in the app. The bin and the filter must be installed and clean, and, if the mop pad or the water tank is in use, they must be seated and the tank filled; a combo robot stops if the tank or the pad is not detected, or if it senses a leak.

Check the dock and the battery. A robot that cannot find the dock stops, so keep the dock against a wall with clear space either side, plugged in, and away from reflective surfaces. A battery that is aging gives short runs. Restart the robot by holding the Clean button and update the software through the app. If it stops in the same place every time, look at that spot for a threshold, a cable or a floor change. Use the app's mission report to see the location. Contact iRobot with the serial number if the errors persist after these checks.

The Combo j7 holds an extendable mopping pad that lifts when it detects carpet, and a robot that stops on a rug edge may be trying to lift the pad and failing.

Check that the pad mechanism moves freely and is not clogged with lint. The j7 also relies on its front camera to recognize obstacles such as cords, and if the camera cannot see in dim light, it can stop and ask for help. The iRobot Home app records the location where it stopped, so open the map and look for a pattern: if it always stops at the same spot, look at that spot for a cable, a sensor line or a tall threshold. A full bin or a missing filter causes a stop, as does a mop tank that has run dry.