System Description
- CAN communication is a multiplex communication system. This enables the system to transmit and receive large quantities of data at high speed by connecting control units with two communication lines (CAN-H and CAN-L).
- Control units on the CAN network transmit signals using the CAN communication control circuit. They receive only necessary signals from other control units to operate various functions.
- CAN communication lines adopt twisted-pair line style (two lines twisted) for noise immunity.
Scheme 3
Each control unit passes an electric current to the termination circuits when transmitting CAN communication signal. The termination circuits produce an electrical potential difference between CAN-H and CAN-L. CAN communication system transmits and receives CAN communication signals by the potential difference.
| Component | Description |
|---|---|
| Main line | CAN communication line between splices |
| Branch line | CAN communication line between splice and a control unit |
| Splice | A point connecting a branch line with a main line |
| Termination circuit | Refer to " CAN COMMUNICATION CONTROL CIRCUIT ". |
COMPONENT DESCRIPTION CHART
Scheme 4
| Component | System description |
|---|---|
| CAN controller | It controls CAN communication signal transmission and reception, error detection, etc. |
| Transceiver IC | It converts digital signal into CAN communication signal, and CAN communication signal into digital signal. |
| Noise filter | It eliminates noise of CAN communication signal. |
| Termination circuit (1) (Resistance of approx. 120 ohms) | It produces potential difference. |
| (1) These are the only control units wired with both ends of CAN communication system. | |
| (1) | These are the only control units wired with both ends of CAN communication system. |
COMPONENT DESCRIPTION CHART
Description
"Diag on CAN" is a diagnosis using CAN communication instead of previous DDL1 and DDL2 communication lines, between control units and diagnosis unit.
Scheme 5
| Name | Harness | Description |
|---|---|---|
| DDL1 | Tx Rx | It is used for trouble diagnosis. (CAN-H and CAN-L are used for controlling) |
| DDL2 | K-LINE | It is used for trouble diagnosis. (CAN-H and CAN-L are used for controlling) |
| Diag on CAN | CAN-H CAN-L | It is used for trouble diagnosis and control. |
HARNESS DESCRIPTION CHART
Abbreviation List
Unit name abbreviations in CONSULT-III CAN diagnosis and in this article are as per the following list.
| Abbreviation | Unit name |
|---|---|
| A-BAG | Air bag diagnosis sensor unit |
| ABS | ABS actuator and electric unit (control unit) |
| BCM | BCM |
| DLC | Data link connector |
| ECM | ECM |
| EPS | EPS control unit |
| I-KEY | Intelligent Key unit |
| IPDM-E | IPDM E/R |
| M&A | Combination meter |
| TCM | TCM |
ABBREVIATION LIST
VEHICLE EQUIPMENT IDENTIFICATION INFORMATION
Note. Check CAN system type from the vehicle shape and equipment.
