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- IGNITION SWITCH EXPRESSION HINT: The type of ignition switch used on this model differs according to the specifications of the vehicle. The expressions listed in the table below are used in this article. Expression Ignition Switch (position) Engine Switch (condition) Ignition Switch off Off Off Ignition Switch ON ON On (IG) Ignition Switch ACC ACC On (ACC) Engine Start START Start
- PRECAUTION Turn the ignition switch off before measuring the resistance of the main wire and the branch wire. After the ignition switch is turned off, check that the key reminder warning system and light reminder warning system are not in operation. Before measuring the resistance, leave the vehicle for at least 1 minute and do not operate the ignition switch, any switches or doors. If doors need to be opened in order to check connectors, open the doors and leave them open. HINT: Operating the ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.
- STEERING SYSTEM HANDLING PRECAUTIONS Care must be taken when replacing parts. Incorrect replacement could affect the performance of the steering system and result in hazards when driving.
- SRS AIRBAG SYSTEM HANDLING PRECAUTIONS This vehicle is equipped with an SRS (Supplemental Restraint System), which includes components such as the driver airbag and front passenger airbag. Failure to carry out service operations in the correct sequence could cause unexpected SRS deployment during servicing and may lead to a serious accident. Before servicing (including installation/removal, inspection and replacement of parts), be sure to read the precautionary notice for the Supplemental Restraint System. Refer to «PRECAUTION»(ref-493514-S12645077492012081000000) .
- BUS LINE REPAIR NOTE: The CANL bus line and CANH bus line must be installed together. When installing, twist the CANL and CANH bus line together. CAN bus lines are likely to be influenced by noise if the bus lines are not twisted together. The difference in length between the CANL bus line and CANH bus line should be less than 100 mm (3.937 in.). Leave approximately 80 mm (3.150 in.) loose in the twisted wires around the connectors. After repairing the bus line with solder, wrap the repaired part with vinyl tape. Refer to «ELECTRONIC CIRCUIT INSPECTION PROCEDURE»(ref-493289-S18206983812012081000000) . NOTE: The ability of the twisted wire harness to resist interference will be lost if bypass wiring is used. Do not use bypass wiring between the connectors.
- CONNECTOR HANDLING When inserting tester probes into a connector, insert them from the rear of the connector. Use a repair wire to check the connector if it is impossible to check resistance from the rear of the connector.
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- CAN NO. 1 BUS CIRCUIT HINT: The brake actuator assembly (skid control ECU) detects and stores steering angle sensor and yaw rate sensor assembly DTCs and performs DTC communication by receiving information from the steering angle sensor and yaw rate sensor assembly. The ECM uses the CAN communication system to perform DTC communication instead of the conventional communication line (SIL).
- CAN NO. 2 BUS CIRCUIT
SYSTEM DESCRIPTION
- BRIEF DESCRIPTION The CAN (Controller Area Network) is a serial data communication system for real time application. It is a vehicle multiplex communication system which has a high communication speed (500 kbps) and the ability to detect malfunctions. By pairing the CANH and CANL bus lines, the CAN performs communication based on differential voltages. Many ECUs (sensors) installed on the vehicle operate by sharing information and communicating with each other. The CAN has 2 resistors of 120 ohms which are necessary to communicate with the main wire.
- DEFINITION OF TERMS Main wire The main wire is a wire harness between the 2 termination circuits on the bus (communication line). This is the main bus in the CAN communication system. Branch wire The branch wire is a wire harness which diverges from the main wire to an ECU or sensor. Termination circuit The termination circuit is a circuit which converts the communication current used in CAN communication into the bus voltage. It consists of a resistor and capacitor. 2 termination circuits are necessary on a bus. CAN J/C The CAN J/C is a junction designed for CAN communication, which contains a termination circuit.
- CIRCUIT DESCRIPTION In vehicles equipped with the smart key system, the CAN communication system is composed of a main body ECU and 2 bus circuits (CAN No. 1 bus and CAN No. 2 bus), which are controlled by the main body ECU. The CAN No. 1 bus and CAN No. 2 bus each have termination circuits which use 120 ohms of resistance, and are capable of high speed communication (500 kbps for the CAN No. 1 bus, and 250 kbps for the CAN No. 2 bus).
- ECU OR SENSOR WHICH COMMUNICATE VIA CAN COMMUNICATION SYSTEM Brake actuator assembly (skid control ECU) Power steering ECU assembly Steering angle sensor Yaw rate sensor assembly ECM Center airbag sensor assembly Air conditioning amplifier assembly Combination meter assembly (combination meter ECU) Main body ECU (driver side junction block) 4WD control ECU assembly*1 ECU aggregation box assembly (certification ECU)*2 *1: for 4WD *2: w/ Smart Key System
- DIAGNOSTIC CODES FOR CAN COMMUNICATION SYSTEM DTCs for the CAN communication system are as follows: U0073, U0100, U0122, U0123, U0124, U0126, U0129, B1207, B1499 and B2326.
- NOTES REGARDING TROUBLESHOOTING Trouble in the CAN bus (communication line) can be checked through the DLC3 (except when there is a wire break in the branch wire of the DLC3). NOTE: Do not connect the tester directly to the DLC3. Be sure to use a service wire. DTCs regarding the CAN communication system can be checked using the Techstream. The CAN communication system cannot detect trouble in the branch line of the DLC3 even though the DLC3 is also connected to the CAN communication system.