MULTIPLEX COMMUNICATION SYSTEM

id100000001400


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/LIN communication/ISO communication/local CAN connection conditions. The availability of the equipment may differ depending on the vehicle specifications.

CAN/LIN communication/ISO communication/local CAN (L.H.D.)

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CAN/LIN communication/ISO communication/local CAN (R.H.D.)

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Local CAN

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Structural view

Note
•  The following figure shows the installation positions for the equipment which perform CAN communication. The availability of the equipment may differ depending on the vehicle specifications.

L.H.D.

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R.H.D.

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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
―  DC-DC converter (i-ELOOP) (with i-ELOOP system)
―  EPS control module
―  BCM
―  TCM (AT)
―  Audio amplifier (with Bose® type audio)
―  Retractable hardtop control module (with retractable hardtop)
―  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 / adaptive LED headlights 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)
―  Climate control unit


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-41 and DSC HU/CM.

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Local CAN

•  Local CAN is used for communication between the following modules:
―  Between PCM and TCM
―  Between connectivity master unit (CMU), DVD/CD player, CD player, and tuner and amp unit (TAU) (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 current sensor
―  Between BCM and electrical supply unit (ESU)
―  Between BCM and intruder sensor
―  Between BCM and theft-deterrent siren
―  Between adaptive front lighting system (AFS) control module and swivel actuator (LH)
―  Between adaptive front lighting system (AFS) control module and swivel actuator (RH)
―  Between adaptive LED headlights control module and front combination light (LH)
―  Between adaptive LED headlights control module and front combination light (RH)
―  Between connectivity master unit (CMU) and commander switch


ISO communication

•  ISO communication is used for communication between the following modules:
―  Between BCM and start stop unit
―  Between Instrument cluster and indicator unit
―  Between indicator unit and seat warmer control 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)
―  Between instrument cluster terminals B (CAN_H) and D (CAN_L)
•  The MS-CAN has terminal resistors built into the following units which form the CAN lines.
―  Between climate control unit terminals D (CAN_H) and B (CAN_L)
―  Between instrument cluster terminals C (CAN_H) and E (CAN_L)


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) (with center display)
―  Between tuner and amp unit (TAU) terminals 2O (CAN_H) and 2Q (CAN_L) (with center display (VIN: JMZ ND6E***# 100001—200000, JM7 ND*****# 100001—200000)) (L.H.D.)
―  Between tuner and amp unit (TAU) terminals 2O (CAN_H) and 2Q (CAN_L) (with center display (VIN: JMZ ND6E***# 100001—300000, JM0 ND2E***# 100001—200000, JM6 ND2E7**# 100001—200000)) (R.H.D.)
―  Between tuner and amp unit (TAU) terminals 1AA (CAN_H) and 1AB (CAN_L) (with center display (VIN: JMZ ND6E***# 200001—, JM7 ND*****# 200001—)) (L.H.D.)
―  Between tuner and amp unit (TAU) terminals 1AA (CAN_H) and 1AB (CAN_L) (with center display (VIN: JMZ ND6E***# 300001—, JM0 ND2E***# 200001—, JM6 ND2E7**# 200001—)) (R.H.D.)
―  Between audio unit terminals 1O (CAN_H) and 1Q (CAN_L) (without center display)
―  Between CD player terminals G (CAN_H) and H (CAN_L) (without center display)
―  Between blind spot monitoring (BSM) control module (LH) terminals G (CAN_H) and J (CAN_L) (with blind spot monitoring (BSM) system)
―  Between blind spot monitoring (BSM) control module (RH) terminals G (CAN_H) and J (CAN_L) (with blind spot monitoring (BSM) system)
―  Between PCM terminals 1A (CAN_H) and 1B (CAN_L)
―  Between TCM terminals 1AI (CAN_H) and 1AE (CAN_L)


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)
―  Current sensor
―  Intruder sensor
―  Theft-deterrent siren
―  Adaptive front lighting system (AFS) control module
―  Swivel actuator (LH)
―  Swivel actuator (RH)
―  Adaptive LED headlights control module
―  Front combination light (LH)
―  Front combination light (RH)
―  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
―  Instrument cluster
―  Seat warmer control unit
―  Indicator unit