Mazda X-5. Manual — part 122

CONTROL SYSTEM

09–40–1

09–40

09–40

CONTROL SYSTEM

CONTROLLER AREA NETWORK (CAN)

SYSTEM OUTLINE . . . . . . . . . . . . . . . . 09–40–1

CAN SYSTEM STRUCTURAL VIEW . . . 09–40–1
CAN SYSTEM WIRING DIAGRAM . . . . . 09–40–1
CAN SYSTEM DESCRIPTION . . . . . . . . 09–40–2

Mechanism of CAN System-Related

Module . . . . . . . . . . . . . . . . . . . . . . . . 09–40–2

Twisted Pair . . . . . . . . . . . . . . . . . . . . . . 09–40–2
Time Division Multiplex . . . . . . . . . . . . . 09–40–3
Vehicle CAN System . . . . . . . . . . . . . . . 09–40–3
CAN Signal-Chart . . . . . . . . . . . . . . . . . 09–40–4
On-Board Diagnostic Function . . . . . . . 09–40–5

End of Toc

CONTROLLER AREA NETWORK (CAN) SYSTEM OUTLINE

E5U094055430N01

• Due to the simplification of the wiring harness, a CAN system for transmission of multiplex input/output signals

among electrical modules has been adopted.

• Twisted-pair wiring is used for connections between the following modules. (Each electrical module hereafter

referred to as a CAN system-related module):

— PCM

— TCM

— DSC HU/CM (with DSC)

— ABS HU/CM (with ABS)

— Keyless control module (with advanced keyless system)

— Steering angle sensor (with DSC)

— Instrument cluster

• With an on-board diagnostic function included for each multiplex module, display of DTCs using the WDS or

equivalent has improved serviceability.

End Of Sie

CAN SYSTEM STRUCTURAL VIEW

E5U094055430N02

End Of Sie

CAN SYSTEM WIRING DIAGRAM

E5U094055430N03

End Of Sie

KEYLESS
CONTROL MODULE

PCM

DSC HU/CM (WITH DSC)
ABS HU/CM (WITH ABS)

INSTRUMENT CLUSTER

TCM (

AT)

STEERING ANGLE
SENSOR (WITH DSC)

E5U940ZS5001

F

E

Z

Y

1J

1L

:

:

CAN_H

CAN_L

DLC-2

1AI

1AM

4AA

4Z

1G

1C

PCM

ABS HU/CM
(WITH ABS)

KEYLESS
CONTROL MODULE
(WITH ADVANCED
KEYLESS SYSTEM)

TCM (AT)

INSTRUMENT
CLUSTER

TWISTED PAIR

X

W

DSC HU/CM
(WITH DSC)

E

F

STEERING
ANGLE
SENSOR
(WITH DSC)

E5U940ZS5002

CONTROL SYSTEM

09–40–2

CAN SYSTEM DESCRIPTION

E5U094055430N04

Mechanism of CAN System-Related Module

• A CAN system-related module is composed of an electrical circuit, CPU, and input/output interface.

• The size of the module has been reduced due to the elimination of the bulky, superfluous, input/output interface

in the conventional type of electrical module.

• The CPU (multiplex block) controls all signals exchanged on the CAN harness.

• Communication with non-multiplex parts is carried out by conventional input/output interface.

• The functions of each component are shown below.

Twisted Pair

• The multichannel use two spirally twisted wires

called a twisted pair, and each wire, CAN_L and
CAN_H, has its own special function.

• Both bus lines are opposite phase voltage. This

allows for minimal noise being emitted and makes
if difficult for noise interference to be received.

Component

Function

Electrical circuit

Supplies power to CPU and vicinity, and to input/output interface.

CPU

Computation processing block Control function has been expanded, and when transmission is necessary,

transmitted data is stored in a multiplex block. If a multiplex block receives a
request to read stored data, transmitted data is read from the multiplex block.

Multiplex block

Transmits data received from bus line to computation processing block. In
addition, sends transmitted data stored from computation processing block to
bus line.

Input/Output interface

Electrically converts information signals from switches to, be input to CPU,
and signals output from CPU for operating actuator or indicator lights.

INPUT
SIGNAL

OUTPUT
SIGNAL

CONNECTOR

INPUT
INTERFACE

OUTPUT
INTERFACE

CPU

CONVENTIONAL MODULE

CPU

CAN HARNESS

(TWISTED PAIR)

CONVENTIONAL
WIRING HARNESS

CONNECTOR

MULTIPLEX
BLOCK

INPUT
INTERFACE

OUTPUT
INTERFACE

COMPUTATION
PROCESSING BLOCK

CAN SYSTEM-RELATED MODULE

C3U0940S006

C A N _ H

C A N _ L

B3E0940T202

CONTROL SYSTEM

09–40–3

09–40

Time Division Multiplex

• For information exchange between electrical modules in a conventional system, a wire connection was

necessary for each information signal. However, by sending the different signal at varying times over one
channel, it is possible to send a large amount of information via a small wiring harness.

• In the conventional, non-multiplex system, in order to control the illumination of the five bulbs, one switch and

one channel was necessary for each bulb. For bulbs B and C to illuminate, switches B and C must be ON and
electricity must flow through the channel. With the time multiplex system, this can be done through one
channel. The channel is comprised of five data signal transmitters which transmit either a “0” or “1” signal to
indicate whether a bulb turns ON or OFF. For example, to illuminate bulbs B and C, transmitters B and C
transmit a “1” and transmitters A, D, and E transmit a “0”. When the receiver receives these signal, bulbs B and
C illuminate.

Vehicle CAN System

• By rearranging the multiple signal, common information between the CAN system-related modules is

transmitted and received through the multichannel.

• The signal transmitted by one CAN system-related module is sent through the multichannel to all the CAN

system-related modules, but only the concerned module (s) receives the signal and performs the appropriate
operation (ex. light illumination, fan operation).

A

0

0

0

1

1

0

0

0

1

1

0

0

0

1

1

0

0 0 1 1 0

0

0

1

1

0

0

0

1

1

B

C

D

E

A

B

C

D

E

A

A

B

C

D

0=OFF
1=ON

E

B

C

D

E

A

B

C

D

E

NON-MULTIPLEX SYSTEM

TIME DIVISION MULTIPLEX SYSTEM

EACH SIGNAL IS TRANSMITTED
ONE BY ONE THROUGH THE
CHANNEL AS IT IS RECEIVED.

EACH SIGNAL IS OUTPUT ONE BY
ONE AS IT IS RECEIVED FROM THE
CHANNEL.

DATA

C3U0940S007

CONVENTIONAL
SYSTEM

ELECTRICAL
MODULE

ELECTRICAL
MODULE

ELECTRICAL
MODULE

CAN SYSTEM-
RELATED
MODULE

CAN SYSTEM-
RELATED
MODULE

CAN SYSTEM-
RELATED
MODULE

CAN SYSTEM

A6A8111T006

CONTROL SYSTEM

09–40–4

CAN Signal-Chart

OUT: Output (sends signal)

IN: Input (receives signal)

Signal

Multiplex module

PCM

TCM

ABS HU/CM

or DSC HU/

CM

Keyless

control

module

Steering

angle

sensor

Instrument

cluster

Engine speed

OUT

IN

IN (DSC)

IN

–

IN

Vehicle speed

OUT

IN

–

IN

–

IN

IN

OUT

–

–

Engine coolant temperature

OUT

IN

–

–

–

IN

Engine torque

OUT

IN

IN (DSC)

–

–

–

Accelerator pedal position

OUT

IN

IN (DSC)

–

–

–

TP

OUT

IN

IN (DSC)

–

–

–

Intake air temperature

OUT

IN

–

–

–

–

Ignition timing

OUT

IN

–

–

–

–

Engine specification

OUT

–

IN

–

–

–

Brake pedal position

OUT

IN

–

–

–

–

Tire circumference (front/rear)

OUT

IN

IN

–

–

–

IN

–

OUT

Immobilizer-related information

OUT

–

–

–

–

IN

IN

–

OUT

Travelled distance

OUT

–

–

–

–

IN

IN

OUT

–

Fuel injection amount

OUT

–

–

–

–

IN

MIL on request

OUT

–

–

–

–

IN

–

OUT

Generator warning light on request

OUT

–

–

–

–

IN

Cruise main/set indicator light on
request

OUT

–

–

–

–

IN

AT gear position/selector lever
position (AT)

IN

OUT

–

–

–

IN

ATF temperature (AT)

IN

OUT

–

–

–

–

Desired gear position (AT)

IN

OUT

IN (DSC)

–

–

–

TCC status (AT)

IN

OUT

IN (DSC)

–

–

–

AT warning light on request (AT)

IN

OUT

–

–

–

IN

Brake system status (EBD/ABS/
DSC)

IN

–

OUT

–

–

–

Wheel speed (LF, RF, LR, RR)

IN

–

OUT

–

–

–

Brake system warning light on
request

–

–

OUT

–

–

IN

ABS warning light on request

–

–

OUT

–

–

IN

DSC indicator light on request

–

–

OUT (DSC)

–

–

IN

DSC OFF light on request

–

–

OUT (DSC)

–

–

IN

Security light on request

–

–

–

OUT

–

IN

Steering angle sensor status

–

–

IN (DSC)

–

OUT

–

Fuel tank level

IN

–

–

–

–

OUT

Parking brake position

–

–

IN (DSC)

–

–

OUT