Menu +
Generic selectors
Exact matches only
Search in title
Search in content

MULTIPLEX COMMUNICATION SYSTEM

 

2016 – MX-5 – Multiplex Communication System

MULTIPLEX COMMUNICATION SYSTEM

Outline

  • A control area network (CAN) system has been adopted in which the multiple control modules send/receive signals using two common communication lines.

  • Local CAN, ISO communication, or LIN communication has been adopted for the individual communication between control modules in consideration of the communication speed and the cost.

System Wiring Diagram

NOTE:

  • The following figure shows the CAN/LIM communication/ISO communication/local CAN connection conditions. Availability depends on the vehicle specification.

CAN/LIN communication/ISO communication

Local CAN

Structural view

Function

CAN (controller area network) system
  • HS-CAN (high-speed controller area network) is used for communication between the following modules:

    • PCM

    • DSC HU/CM

    • EVP control unit

    • EPS control module

    • BCM

    • TCM (AT)

    • Audio amplifier (With Bose® type audio)

    • Occupant classification sensor (with occupant classification sensor)

    • Forward sensing camera (FSC) (With forward sensing camera (FSC))

    • Adaptive front lighting system (AFS) control module / auto leveling control module

    • Start stop unit

    • Connectivity master unit (CMU) (with center display)

    • SAS control module

    • Instrument cluster

  • MS-CAN (mid-speed controller area network) is used for communication between the following modules:

    • Instrument cluster

    • Blind spot monitoring (BSM) control module (LH) (with blind spot monitoring (BSM) system)

    • Climate control unit (full-auto air conditioner)

    • Climate control unit (Manual air conditioner)

  • Signals transmitted using the CAN system are as follows:

HS-CAN communication tableOUT: Output (sends signal)IN: Input (receives signal)

Signal

CAN system related module

PCM

TCM

Adaptive front lighting system (AFS) control module /

auto leveling control module

DSC HU/CM

EVP control unit

EPS control module

BCM

Forward sensing camera (FSC)

Instrument cluster

Start stop unit

SAS control module

Occupant classification sensor

Connectivity master unit (CMU)

Audio amplifier

Acceleration signal status

IN

OUT

Accelerator pedal opening angle information

OUT

IN

IN

IN

IN

IN

IN

AFS (adaptive front lighting system) OFF switch status

IN

OUT

AFS (adaptive front lighting system) level configuration

OUT

IN

IN

AFS (adaptive front lighting system) warning status

OUT

IN

IN

Air bag/front seat belt pre-tensioner system warning light on request

IN

IN

OUT

IN

IN

IN

IN

OUT

IN

Air bag system warning buzzer on request

IN

OUT

IN

Air bag system-related information

IN

OUT

IN

AT shift position

IN

OUT

Air conditioner signal

OUT

IN

AT gear position

OUT

IN

IN

AT/MT gear position

OUT

IN

IN

Ambient temperature

IN

IN

IN

IN

IN

IN

IN

OUT

IN

IN

IN

IN

OUT

IN

IN

IN

IN

IN

IN

Audio configuration information

IN

IN

IN

IN

IN

OUT

IN

IN

IN

A/C operation signal

IN

OUT

IN

Alarm status

OUT

IN

IN

Brake fluid level

OUT

IN

IN

Battery discharge suppression status

OUT

IN

IN

Battery charge status

IN

IN

IN

IN

IN

IN

OUT

IN

IN

IN

IN

Battery regeneration status

OUT

IN

IN

Blower motor relay status

OUT

IN

Back-up light on request

IN

IN

IN

OUT

IN

Brake switch status

OUT

IN

IN

Brake switch (No.1) signal

OUT

IN

IN

IN

IN

IN

IN

IN

Brake switch (No.2) signal

OUT

IN

IN

IN

IN

IN

IN

Blind spot monitoring (BSM) control module configuration information

IN

IN

IN

IN

IN

OUT

IN

IN

IN

Blind spot monitoring (BSM) system activation request

OUT

IN

Blind spot monitoring (BSM) system-related information

OUT

IN

Blind spot monitoring (BSM) system personalization-related information

IN

OUT

OUT

IN

Blower speed

OUT

IN

Cruise control system-related information

IN

OUT

OUT

IN

Cruise control switch

IN

IN

OUT

IN

OUT

IN

OUT

IN

IN

IN

IN

Cruise control set speed

OUT

IN

Cranking start

IN

IN

IN

OUT

Cranking time

OUT

IN

IN

Charging system warning light on request

OUT

IN

IN

Cluster switch status

IN

IN

OUT

Clutch status

OUT

IN

Clutch pedal stroke sensor

OUT

IN

Collision detection (front, side, roll over)

IN

IN

IN

OUT

IN

Collision detection (rear)

IN

IN

IN

OUT

IN

Charging system warning light on request

OUT

IN

IN

IN

DSC system-related information

IN

IN

OUT

IN

IN

IN

IN

IN

OUT

IN

Dimmer cancel

OUT

IN

IN

Disabling of brake override system signal

OUT

IN

IN

IN

Driver-side buckle switch status

IN

IN

IN

IN

OUT

IN

Driving condition

IN

IN

IN

IN

IN

IN

OUT

IN

IN

IN

IN

Door status

IN

OUT

IN

IN

IN

IN

EVP control unit-related information

IN

OUT

IN

Engine switch status

OUT

IN

IN

IN

IN

IN

OUT

IN

IN

Engine off time

IN

IN

IN

OUT

IN

Engine Status

OUT

IN

IN

IN

IN

IN

IN

IN

IN

Engine torque

OUT

IN

IN

Engine rotation speed

OUT

IN

IN

IN

IN

IN

IN

IN

IN

IN

Engine switch status

IN

IN

IN

IN

IN

IN

OUT

IN

IN

IN

IN

Engine coolant temperature

OUT

IN

IN

IN

Engine stop request

IN

OUT

IN

Engine displacement

OUT

IN

IN

IN

IN

IN

IN

IN

EPS status

IN

OUT

IN

IN

Fuel tank level

IN

OUT

IN

Forward sensing camera personalization-related information

IN

OUT

Forward sensing camera customize request

OUT

IN

Fuel cut request

IN

IN

IN

IN

OUT

IN

Fuel cap warning light on request

OUT

IN

IN

Fuel-level sensor-related information

OUT

IN

Fuel economy information reset request signal

IN

OUT

Front combination light on request

IN

OUT

Gear position

OUT

IN

IN

IN

IN

OUT

IN

IN

IN

IN

IN

IN

IN

Global central configuration error

OUT

IN

IN

Global central configuration

IN

IN

IN

IN

IN

IN

OUT

IN

IN

IN

IN

Glow indicator light illumination request

OUT

IN

IN

Hazard warning switch information

IN

IN

IN

OUT

Horn control

IN

OUT

High-beam indicator

OUT

IN

IN

IN

Headlight information

IN

IN

OUT

IN

IN

IN

Headlight warning request signal

OUT

IN

IN

Hands-free telephone system-related information

IN

IN

IN

IN

IN

IN

OUT

IN

IN

IN

Heater control unit configuration information

IN

IN

IN

IN

IN

OUT

IN

IN

IN

High-beam control personalization-related information

IN

OUT

OUT

IN

Immobilizer-related information

OUT

IN

IN

OUT

Instrument cluster personalization-related information

IN

OUT

OUT

IN

ID data

OUT

IN

Ignition off timer

IN

IN

IN

IN

IN

IN

IN

OUT

IN

IN

IN

IN

Key status

OUT

IN

IN

Keyless warning alarm activation request

IN

OUT

IN

Keyless indicator light on request

IN

OUT

IN

OUT

IN

IN

Light switch information

IN

IN

IN

OUT

Light switch TNS (Parking Lights) signal

IN

IN

IN

OUT

Light switch LO signal

IN

IN

OUT

Light switch HI signal

IN

IN

OUT

Light switch OFF signal

IN

IN

OUT

Lock/Unlock status

OUT

IN

Leveling warning status

OUT

IN

IN

Manual shift control

IN

OUT

OUT

IN

MT gear position

OUT

IN

IN

IN

IN

IN

MIL on request

OUT

IN

IN

Master warning light on request signal

IN

OUT

Neutral switch status

OUT

IN

IN

IN

IN

IN

Oil warning light on request

OUT

IN

IN

Oil level warning limit

OUT

IN

Oil level warning

OUT

IN

Power supply status

IN

IN

IN

OUT

Passing switch status

IN

IN

IN

OUT

Parking brake status

IN

IN

IN

IN

OUT

IN

Panel light on request

OUT

IN

Panel light level

OUT

IN

IN

PAD indicator on status

OUT

IN

Power consumption

IN

OUT

IN

Power supply status

IN

OUT

IN

Push button system-related information

IN

OUT

IN

Passenger-side buckle switch status

IN

OUT

IN

Rolling counter

IN

OUT

Rear window defogger information

IN

OUT

IN

IN

Rear window defogger operation request

IN

OUT

ROOM fuse status

IN

IN

OUT

Steering angle (absolute angle) signal

IN

OUT

Steering angle (estimated absolute angle) signal

IN

IN

IN

IN

OUT

IN

IN

IN

IN

Steering angle condition

IN

OUT

IN

Steering shift switch

IN

OUT

Seat warmer cut status

OUT

IN

Security indicator light on request

IN

OUT

IN

Starter relay status

OUT

IN

Supply voltage

IN

IN

IN

IN

IN

IN

OUT

IN

IN

IN

IN

Steering angle condition

IN

IN

IN

IN

IN

IN

OUT

IN

IN

IN

Seat belt status

OUT

IN

IN

Start stop unit personalization-related information

IN

OUT

OUT

IN

Turn switch status

IN

IN

IN

IN

OUT

Turn indicator light on request

OUT

IN

IN

IN

TPMS OFF switch status

IN

OUT

IN

TNS (Parking Lights) status

OUT

IN

IN

IN

Target gear position

OUT

IN

IN

IN

IN

Traveled distance

IN

IN

IN

IN

IN

IN

IN

OUT

IN

IN

IN

IN

Tire circumference

IN

IN

IN

IN

IN

IN

OUT

IN

IN

IN

Temperature control dial status

IN

OUT

IN

Transmission type

OUT

IN

IN

IN

Temperature unit switch signal

IN

OUT

Tuner and amp unit communication status signal

IN

OUT

Traveled distance

OUT

IN

IN

Vehicle speed

OUT

IN

IN

IN

IN

IN

IN

IN

IN

IN

IN

IN

OUT

IN

IN

IN

IN

IN

IN

Wheel speed

IN

IN

OUT

IN

IN

IN

IN

IN

IN

Washer level sensor status

OUT

IN

IN

Wiper (INT) status

IN

OUT

Wiper switch status

IN

IN

OUT

Wiper status

IN

IN

OUT

Wiper operation signal

IN

IN

OUT

IN

IN

IN

Washer switch information

IN

IN

OUT

Maintenance monitor-related information

IN

OUT

Warning guidance-related information

IN

OUT

Yaw rate

IN

OUT

IN

IN

OUT

IN

IN

IN

IN

IN

MS-CAN communication tableOUT: Output (sends signal)IN: Input (receives signal)

Signal

CAN system related module

Climate control unit

Instrument cluster

Blind spot monitoring (BSM) control module (LH)

Air bag/front seat belt pre-tensioner system warning light on request

IN

OUT

Air conditioner signal

IN

OUT

Ambient temperature

IN

OUT

IN

Audio configuration information

IN

OUT

IN

Ambient temperature

IN

OUT

A/C operation signal

OUT

IN

Blower motor relay status

IN

OUT

Blind spot monitoring (BSM) switch information

OUT

IN

Blind spot monitoring (BSM) control module configuration information

IN

OUT

IN

Blind spot monitoring (BSM) system activation request

IN

OUT

Blind spot monitoring (BSM) system-related information

IN

OUT

Blind spot monitoring (BSM) system personalization-related information

OUT

IN

IN

OUT

Blower speed

OUT

IN

Back-up light on request

OUT

IN

Battery charge status

IN

OUT

IN

Cranking start

IN

OUT

Cluster switch status

OUT

IN

Dimmer cancel

IN

OUT

IN

Drive information system date

IN

OUT

Driving condition

IN

OUT

IN

Engine Status

IN

OUT

Engine switch status

IN

OUT

IN

Engine off time

IN

OUT

Engine rotation speed

IN

OUT

Engine coolant temperature

IN

OUT

Engine stop request

OUT

IN

Engine displacement

IN

OUT

Gear position

OUT

IN

Global central configuration

IN

OUT

IN

Hands-free telephone system-related information

IN

OUT

IN

Heater control unit configuration information

IN

OUT

IN

Ignition off timer

IN

OUT

IN

Panel light on request

IN

OUT

IN

Panel light level

IN

OUT

Rear window defogger information

IN

OUT

Rear window defogger operation request

OUT

IN

ROOM fuse status

IN

OUT

Supply voltage

IN

OUT

IN

Steering angle condition

IN

OUT

IN

Steering angle (estimated absolute angle) signal

OUT

IN

Temperature control dial status

OUT

IN

Turn switch status

OUT

IN

Tire circumference

IN

OUT

IN

Traveled distance

IN

OUT

IN

Vehicle speed

IN

OUT

IN

Wiper operation signal

IN

OUT

Yaw rate

OUT

IN

Malfunction diagnosis procedure
  • If a vehicle with a malfunction in a system controlled by a CAN system related module is brought in, verify the repair order form and the malfunctioning symptom first, then perform CAN malfunction diagnosis to determine if the malfunction cause is in the CAN system or not.

  • For CAN malfunction diagnosis, the voltage at the CAN connection terminal on the DLC-2 is measured, and based on the measured value, the CAN circuit can be examined or the malfunction symptom can be determined.

  • If the malfunction symptom is not an open circuit, inspect the voltage or continuity at the CAN circuit and determine the malfunctioning location.

  • If the malfunction symptom is an open circuit, determine the area of the open circuit by using the displayed communication error DTC and the module in which communication has failed.

Ex.) Open circuit location determination procedure

1. Verify the CAN system-related module DTCs and the failed module using the Mazda Modular Diagnostic System (M-MDS).

DTC output module

Mazda Modular Diagnostic System (M-MDS) display

Output DTC

PCM

PCM

U0121:00

EVP control unit

EVP

U0121:00

U0121:02

U0121:87

EPS control module

EPS

U0121:00

BCM

BCM

U0121:00

TCM

TCM

U0121:00

Forward sensing camera (FSC)

FSC

U0121:00

Start stop unit

SSU

U0121:00

U0121:87

Connectivity master unit (CMU)

CMU

U0121:00

Instrument cluster

IC

U0121:00

Module

Fail display

DSC HU/CM

×

2. As a result of DTC verification, only DTCs related to DSC HU/CM and communication errors are output and the DSC HU/CM is indicated as failed, therefore there could be a malfunction in the DSC HU/CM or in the wiring harness between connector C-26, C-27 and DSC HU/CM.

Local CAN
  • Local CAN is used for communication between the following modules:

    • Between PCM and TCM (AT)

    • Between connectivity master unit (CMU), CD player, and tuner and amp unit (with center display)

    • Between audio unit, Bluetooth® unit, and CD player (without center display)

    • Between blind spot monitoring (BSM) control module (LH) and blind spot monitoring (BSM) control module (RH) (with blind spot monitoring (BSM) system)

LIN communication
  • LIN communication is used for communication between the following modules:

    • Between BCM and auto light sensor / rain sensor

    • Between BCM and electrical supply unit (ESU)

    • Between connectivity master unit (CMU) and commander switch

ISO communication
  • ISO communication is used for communication between the following modules:

    • Between rear BCM and start stop unit

Construction

CAN
  • The HS-CAN has terminator resistors built into the following units which form the CAN lines.

    • Between PCM terminals 2AK (CAN_H) and 2AL (CAN_L), resistance value: 124 ohms

    • Between instrument cluster terminals B (CAN_H) and D (CAN_L), resistance value: 120 ohms

  • The MS-CAN has terminal resistors built into the following units which form the CAN lines.

    • Between instrument cluster terminals C (CAN_H) and E (CAN_L), resistance value: 120 ohms

    • Between climate control unit terminals D (CAN_H) and B (CAN_L), resistance value: 120 ohms

Local CAN
  • The local CAN has terminator resistors built into the following units which form the CAN lines.

    • Between connectivity master unit (CMU) terminals 2I (CAN_H) and 2J (CAN_L), resistance value: 120 ohms (with center display)

    • Between tuner and amp unit terminals 2O (CAN_H) and 2Q (CAN_L), resistance value: 120 ohms (with center display)

    • Between audio unit terminals 1O (CAN_H) and 1Q (CAN_L), resistance value: 120 ohms (without center display)

    • Between CD player terminals G (CAN_H) and H (CAN_L), resistance value: 120 ohms (without center display)

    • Between blind spot monitoring (BSM) control module (LH) terminals G (CAN_H) and J (CAN_L), resistance value: 120 ohms (with blind spot monitoring (BSM) system)

    • Between blind spot monitoring (BSM) control module (RH) terminals G (CAN_H) and J (CAN_L), resistance value: 120 ohms (with blind spot monitoring (BSM) system)

    • Between PCM terminals 1A (CAN_H) and 1B (CAN_L), resistance value: 120 ohms

    • Between TCM terminals 1AI (CAN_H) and 1AE (CAN_L), resistance value: 120 ohms

LIN communication
  • The LIN communication has drivers built into the following units which form the LIN communication lines.

    • BCM

    • Auto light sensor / rain sensor

    • Electrical supply unit (ESU)

    • Connectivity master unit (CMU)

    • Commander switch

ISO communication
  • The ISO communication has drivers built into the following units which form the ISO communication lines.

    • Start stop unit

    • BCM

 

© 2014 Mazda North American Operations, U.S.A.