Pet robot II not working

I have an issue with my robot II: when powering the robot, the motor start and stops less than half a sec. later. The light ‘in use/cycling’ is on.
I replaced the presence sensor but same issue. I opened the robot and the wires seem properly connected. What component might be failing?

@mailysrobin

Hi,
The issue could be caused either by the circuit board or the motor itself.
We suggest you take a look at the basic troubleshooting guide: robotshop.com/blog/en/litte … uide-13929