I have 08 ford escape when I try to scan it said no communication

Do you know about communication networks or serial data communications on vehicles , these let the scan tool communicate with the different modules on the vehicle ! Newer vehicles have several, PCM - powertrain control module , Anti-theft module , Air bags , antilock brakes , Body control module or in the case of ford a smart junction box . an some others !
Communications Network Vehicle communication utilizes both International Standards Organization (ISO) 9141 and controller area network (CAN) communications. ISO 9141 is used for diagnostic use only, and CAN is used for many modules to communicate with each other on a common network. CAN in-vehicle networking, is a method for transferring data among distributed electronic modules via a serial data bus. Without serial networking, intermodule communication requires dedicated, point to point wiring resulting in bulky, expensive, complex, and difficult to install wiring harnesses. Applying a serial data network reduces the number of wires combining the signals on a single network. Information is sent to the individual control modules that control each function.
The vehicle has 3 module communication networks:

• ISO 9141
• Medium speed (MS) CAN
• High speed (HS) CAN

• ABS module
• 4WD control module (if equipped)
• Instrument cluster
• PCM
• MS-CAN Network Operation
  The MS-CAN network communicates using bussed messages. The MS-CAN has an unshielded twisted pair cable, data bus (+) and data bus (-) circuits. In addition to scan tool communication, this network allows sharing of information between all modules on the network.
  The MS-CAN is a medium speed communication network used for the following modules:
  
  • Instrument cluster
  • SJB
  HS-CAN Network
  
• What type of scan tool are you using ? or are you using a code reader ?
• 
  What