When working with ECU or TCU, you need to connect to the OBDII port of the truck and the internal CAN-BUS of the truck simultaneously . Connect the ZN151 to the AVDI, connect the OBDII cable to the DS-Box. Find the internal CAN H (BLUE) and CAN L (WHITE) wires, which connect the CPC and ECU units. Connect to them using the needle pinch connectors supplied with the ZN151 set, and make sure you use 3-11 slots on the DS-Box. Always refer to a factory wiring diagram because unlike with cars – trucks are not always the same color, this based on our experience so far.