Makeblock mBot Manual page 25

If the LED corresponding to each sensor lights up when you put the sensor above a white
paper/desk and goes off when it is away from white paper/desk, which means the line follower
sensor is ok. Otherwise, the sensor should be faulty.
If the sensor is ok according to the above test but the line follower mode doesn't work, there are
several possible reasons that we should check.
a. The default program may not function properly in mBot, please refer to FAQ3 to reset default
program to have a try.
b. Make sure you have pressed Button C to enter Line Follower Mode if you use the IR remote
controller to control the mBot.
c. The Me Line Follower sensor may not be connected to the correct RJ25 port. Please connect
the Line follower sensor to the Port 2 on mCore board.
25