The Pit Lane (30356) can be used with either Black Box (30344) or Control Unit (30352). The following tank modes must, however, be observed:
1) Control Unit(30352) Operation: after running over the Fuel Sensor, the car switches into "Fuel" mode. Your car can then be filled manually.
2) Black Box(30344) Operation: once your car entering the Pit Lane (30356) and stops, it will automatically be filled whether it has run over the Fuel Sensor or not.
Further instruction and description of the Pit Lane and Pit Lane with the Driver Display (30353)(you tube)..Very good, produced by Carrera.
The PDF link below explains all the new Carrera digital track items. You must have the 30352 control unit to operate the other items. Feature Guide (pdf)