Lexus ES manuals

Lexus ES: System Description

SYSTEM DESCRIPTION

BRIEF DESCRIPTION

(a) 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.

(b) 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.)

(c) Many ECUs or sensors installed to the vehicle operate by sharing information and communicating with each other.

(d) 2 resistors which are necessary for communication are used in a CAN bus main line.

DEFINITION OF TERMS

(a) Central bus

(1) The central bus is a term used to describe all buses directly connected to the central gateway ECU (network gateway ECU).

HINT:

A bus is displayed as Bus on the "Communication Bus Check" screen of the Techstream.

(b) Sub bus

(1) A sub bus is a bus that has a gateway function equipped ECU in order to communicate with the central bus and other sub buses.

HINT:

  • A sub bus is displayed as Sub bus on the "Communication Bus Check" screen of the Techstream.
  • When Sub bus is selected on the "Communication Bus Check" screen, ECUs and sensors connected to non-CAN networks such as LIN may also be displayed in addition to the ECUs and sensors connected to sub buses in the CAN network.

(c) Local bus

(1) A local bus is a bus that does not have the ability to communicate with other buses. ECUs and sensors on a local bus can only communicate with other ECUs and sensors on the same bus.

(d) CAN J/C

(1) A CAN junction connector is a connector that connects branch lines to a main bus.

(e) Main bus

(1) A main bus line is the wire harness that runs between the 2 terminating resistors of a bus.

(f) Branch

(1) A branch line is a wire harness that connects an ECU or sensor to a main bus line.

(g) Terminating resistors

(1) Terminating resistors which maintain a stable signal inside the CAN bus are installed. 2 resistors of 120 Ω each located at each end of the bus are necessary.

READ NEXT:

 System Diagram

SYSTEM DIAGRAM (a) The CAN communication system is composed of 5 buses. CAN Main Bus Line Terminating Resistor CAN Branch Line * Gateway Function Equipped ECU Bus Monitor

 Parts Location

PARTS LOCATION ILLUSTRATION *1 SWING GRILLE ACTUATOR ASSEMBLY *2 MILLIMETER WAVE RADAR SENSOR ASSEMBLY *3 HEADLIGHT ECU SUB-ASSEMBLY RH *4 INVERTER WITH CONVERTER ASSEMBLY *5

 Precaution

PRECAUTION NOTICE FOR INITIALIZATION NOTICE: When disconnecting the cable from the negative (-) auxiliary battery terminal, initialize the following systems after the cable is reconnected. System

SEE MORE:

 Variation Code not Written (B2451)

DESCRIPTION The headlight ECU sub-assembly LH stores this DTC if the vehicle specifications have not been stored. for LED Type Turn Signal Light DTC No. Detection Item DTC Detection Condition Trouble Area DTC Output from B2451 Variation Code not Written The engine switch is on

 Indicator (Green) Circuit Short to Ground (B157111,B157113)

DESCRIPTION This DTC is set when the DCM (telematics transceiver) detects an open or short in the manual (SOS) switch green indicator circuit of the manual (SOS) switch. The manual (SOS) switch green indicator illuminates after the power switch is turned on (IG). If the safety connect system is not

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