System Description [09/2014 - 10/2015]

1. The Controller Area Network (CAN) is a serial data communication system for real time application. It is a vehicle multiplex communication system which has a high communication speed and the ability to detect malfunctions.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

2. Using the CANH and CANL bus lines as a pair, CAN communication is performed using a voltage differential. (A base voltage is applied to the pair of lines and a voltage differential is created when communicating.)
3. Many ECUs or sensors installed on the vehicle operate by sharing information and communicating with each other.
4. The CAN has two resistors of 120 Ω which are necessary to enable communication.
5. Control system CAN is composed of 7 buses*1 or 9 buses*2.
   1. *1: w/o Dynamic Rear Steering System
   2. *2: w/ Dynamic Rear Steering System

1. Main bus line
   1. The main bus line is a wire harness between the two terminating resistors on the bus. This is the main bus in the CAN communication system.
2. Branch line
   1. The branch line is a wire harness which diverges from the main bus line to an ECU or sensor.
3. Terminating resistors
   1. Two resistors of 120 Ω are installed in parallel across the ends of the CAN main bus lines. They are called terminating resistors. These resistors allow the changes of the voltage differential between the CAN bus lines to be accurately judged. To allow proper function of CAN communication, it is necessary to have both terminating resistors installed. Since the two resistors are installed in parallel, this results in a measurement of approximately 60 Ω.

1. V Bus
   1. ECM
   2. Parking brake ECU assembly
   3. Main body ECU (multiplex network body ECU)
   4. Brake actuator assembly (skid control ECU)
   5. Combination meter assembly
   6. Headlight swivel ECU assembly (AFS ECU)
   7. Spiral with sensor cable sub-assembly (steering angle sensor)
   8. Yaw rate sensor
   9. Multi-media module receiver assembly
   10. Power steering ECU assembly
   11. Center airbag sensor assembly
   12. Front steering control ECU*1
   13. Air conditioning amplifier assembly
   14. Network gateway ECU*2
   15. Certification ECU (smart key ECU assembly)
       1. *1: w/ Variable Gear Ratio Steering System
       2. *2: w/ Network Gateway ECU
2. Sub Bus 2 (w/ Network Gateway ECU)
   1. Network gateway ECU
   2. 4WD ECU Assembly*1
   3. Absorber control ECU*2
   4. Driving support ECU assembly*3
   5. Clearance warning ECU assembly*4
   6. Blind spot monitor sensor RH*5
   7. Seat belt control ECU*6
   8. DCM (telematics transceiver)*7
   9. Rear television camera assembly
      1. *1: for AWD
      2. *2: w/ Adaptive Variable Suspension System
      3. *3: w/ Dynamic Radar Cruise Control System
      4. *4: w/ Intuitive Parking Assist System
      5. *5: w/ Blind Spot Monitor System
      6. *6: w/ Pre-collision System
      7. *7: w/ Manual (SOS) Switch
3. Sub Bus 1
   1. Main body ECU (multiplex network body ECU)
   2. Luggage closer motor assembly*1
   3. Front multiplex network door ECU LH
   4. Front multiplex network door ECU RH
   5. Multiplex tilt and telescopic ECU
   6. Position control ECU assembly LH*2
   7. Power seat switch assembly*3
   8. Position control ECU assembly RH*4
      1. *1: w/ Power Trunk Lid System
      2. *2: except Standard Seat Type
      3. *3: for Standard Seat Type
      4. *4: for Luxury Seat Type
4. Sub Bus 13 (w/ Dynamic Radar Cruise Control System)
   1. Driving support ECU assembly
   2. Millimeter wave radar sensor assembly
   3. Driver monitor ECU assembly*1
   4. Lane recognition camera sensor assembly*2
   5. No. 1 night view ECU*3
      1. *1: w/ Pre-collision System
      2. *2: w/ Lane-keeping Assist System
      3. *3: w/ Night View System
5. Sub Bus 15
   1. ECM
   2. Certification ECU (smart key ECU assembly)
6. Powertrain Bus (for AA81E)
   1. ECM
   2. Transmission control ECU assembly
7. Sensor Bus (w/ Blind Spot Monitor System)
   1. Blind spot monitor sensor RH
   2. Blind spot monitor sensor LH

1. V Bus
   1. ECM
   2. Parking brake ECU assembly
   3. Main body ECU (multiplex network body ECU)
   4. Brake actuator assembly (skid control ECU)
   5. Combination meter assembly
   6. Headlight swivel ECU assembly (AFS ECU)
   7. Spiral with sensor cable sub-assembly (steering angle sensor)
   8. Yaw rate sensor
   9. Multi-media module receiver assembly
   10. Power steering ECU assembly
   11. Center airbag sensor assembly
   12. Front steering control ECU
   13. Air conditioning amplifier assembly
   14. Network gateway ECU
   15. Certification ECU (smart key ECU assembly)
2. Sub Bus 18
   1. Network gateway ECU
   2. Absorber control ECU*1
   3. Driving support ECU assembly*2
   4. Clearance warning ECU assembly*3
   5. Blind spot monitor sensor RH*4
   6. Seat belt control ECU*5
   7. DCM (telematics transceiver)*6
   8. Rear television camera assembly
      1. *1: w/ Adaptive Variable Suspension System
      2. *2: w/ Dynamic Radar Cruise Control System
      3. *3: w/ Intuitive Parking Assist System
      4. *4: w/ Blind Spot Monitor System
      5. *5: w/ Pre-collision System
      6. *6: w/ Manual (SOS) Switch
3. Sub Bus 19
   1. ECM
   2. Network gateway ECU
   3. Front steering control ECU
   4. Power steering ECU assembly
   5. Absorber control ECU*1
   6. Driving support ECU assembly*2
   7. Brake actuator assembly (skid control ECU)
   8. Rear steering control ECU
      1. *1: w/ Adaptive Variable Suspension System
      2. *2: w/ Dynamic Radar Cruise Control System
4. Sub Bus 1
   1. Main body ECU (multiplex network body ECU)
   2. Luggage closer motor assembly*
   3. Front multiplex network door ECU LH
   4. Front multiplex network door ECU RH
   5. Multiplex tilt and telescopic ECU
   6. Position control ECU assembly LH
      1. *: w/ Power Trunk Lid System
5. Sub Bus 13 (w/ Dynamic Radar Cruise Control System)
   1. Driving support ECU assembly
   2. Millimeter wave radar sensor assembly
   3. Driver monitor ECU assembly*1
   4. Lane recognition camera sensor assembly*2
   5. No. 1 night view ECU*3
      1. *1: w/ Pre-collision System
      2. *2: w/ Lane-keeping Assist System
      3. *3: w/ Night View System
6. Sub Bus 15
   1. ECM
   2. Certification ECU (smart key ECU assembly)
7. Powertrain Bus (for AA81E)
   1. ECM
   2. Transmission control ECU assembly
8. Sensor Bus (w/ Blind Spot Monitor System)
   1. Blind spot monitor sensor RH
   2. Blind spot monitor sensor LH
9. Local Bus
   1. Front steering control ECU
   2. Rear steering control ECU

1. w/o Dynamic Rear Steering System:

   The V bus, sub bus 1, sub bus 2, sub bus 13, sub bus 15, powertrain bus and sensor bus and each have termination circuits with two resistors of 120 Ω.

2. w/ Dynamic Rear Steering System:

   The V bus, sun bus 1, sub bus 13, sub bus 15, sub bus 18, sub bus 19, powertrain bus, local bus and sensor bus and each have termination circuits with two resistors of 120 Ω.

1. DTCs for the CAN communication system can be checked using the Techstream. The DLC3 is connected to the CAN communication system, but no DTCs exist regarding problems in the DLC3 or the DLC3 branch lines. If there is any trouble in the DLC3 or the DLC3 branch lines, ECUs on the CAN network cannot output codes to the Techstream.
2. Trouble in the CAN V bus (communication lines) can be checked by measuring the resistance between terminals of the DLC3. However, an open circuit in a branch line other than the DLC3 branch lines cannot be checked from the DLC3 (except branch line of the DLC3).
   NOTE:

   Do not insert the tester probes directly into the DLC3. Be sure to use service wires.

HINT: 

See Diagnosis System (Refer to DIAGNOSIS SYSTEM [09/2014 - 10/2015] ).

1. In the CAN communication system, the shape of connectors connected to the CAN junction connector which has a ground terminal is the same. The connectors connected to the CAN junction connector can be distinguished by the colors of the bus lines and the connecting side of the junction connector.

   HINT: 

   See Terminals of ECU for bus line color or the shape of connecting surface (Refer to TERMINALS OF ECU [09/2014 - 10/2015] ).