Mazda 6. Manual - part 57

 

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Mazda 6. Manual - part 57

 

 

MULITIPLE COMMUNICATION SYSTEM 

T–9

T

T

End Of Sie

CAN SIGNAL-CHART

A6E811155430T08

OUT: Output (sends signal)

IN: Input (receives signal)

End Of Sie

Signal

Multiplex module

PCM

ABS (ABS/TCS) HU/

CM or DSC HU/CM

Instrument cluster

Audio unit

(information 

display)

Engine condition

OUT

IN

Torque reduction inhibit

OUT

IN

Engine speed

OUT

IN

IN

Wheel speed 
(front left/front 
right/rear left/
rear right)

With ABS (ABS/
TCS) or DSC

IN

OUT

OUT

IN

Without ABS

OUT

IN

TP

OUT

IN

ECT

OUT

IN

Travelled 
distance

IN

OUT

MTX, without 
ABS

OUT

IN

Fuel injection amount

OUT

IN

MIL condition

OUT

IN

Generator warning light conditions

OUT

IN

Engine displacement

OUT

IN

Number of cylinders

OUT

IN

Air induction type

OUT

IN

Fuel type and delivery

OUT

IN

Country

OUT

IN

Transmission/axle type

OUT

IN

Tire circumference (front/rear)

OUT

IN

Desired gear/Change lever 
position

OUT

IN

IN

HOLD switch conditions

OUT

IN

Torque reduction request

IN

OUT

Brake system configuration (EBD/
ABS/TCS/DSC)

IN

OUT

IN

Brake system 
status

ABS

IN

OUT

EBD/ABS/TCS/
DSC 

OUT

IN

Brake system warning light 
conditions (brake fluid level 
sensor)

IN

OUT

ABS configuration

IN

IN

OUT

Drive information system switch 
operation

IN

OUT

Drive information system display

OUT

IN

T–10

MULITIPLE COMMUNICATION SYSTEM 

ON-BOARD DIAGNOSTIC FUNCTION

A6E811155430T09

Outline

The on-board diagnostic function is incorporated into the PCM, ABS (ABS/TCS) HU/CM (with ABS (ABS/
TCS)), DSC HU/CM (with DSC), and instrument cluster. This function can narrow down CAN system 
malfunction locations.

The on-board diagnostic function consists of the following functions: a failure detection function, which detects 
malfunctions in CAN system-related parts; a memory function, which stores detected DTCs; a self-malfunction 
diagnostic function, which indicates system malfunctions using DTCs and warning lights; and a PID/data 
monitoring function, which verifies the input/output condition of specific input/output signals being read out. 

Using an SST (WDS or equivalent), DTCs can be read out and deleted, and the PID/data monitoring function 
can be activated.

The CAN system has a fail-safe function. When a malfunction occurs in CAN system, the transmission module 
sends a warning signal and the receiving module illuminates the warning light.

Block Diagram

.

Failure detection function

The failure detection function in each CAN system-related module detects malfunctions in input/output signals.

This function outputs the DTC for the detected malfunction to the DLC-2, and also sends the detected result to 
the memory function and fail-safe function.

Fail-Safe Function

When the failure detection function determines that there is a malfunction, the fail-safe function illuminates a 
warning light to advise the driver of the malfunction.

Memory Function

The memory function stores the DTC for the malfunction of input/output signals for related parts, as determined 
by the failure detection function.

A6E8111T007

1

ABS (ABS/TCS) HU/CM or DSC HU/CM

2

Instrument cluster

3

Twist  pair

Module

Fail-safe functionì®Ì§ä

PCM

MIL illuminated

ABS (ABS/TCS) HU/CM
(with ABS (ABS/TCS))

DSC HU/CM (with DSC)

ABS (ABS/TCS) suspended (with ABS (ABS/TCS))

DSC suspended (with DSC)

ABS warning light illuminated

DSC/TCS indicator light illuminated

DSC OFF light illuminated

TCS OFF light illuminated

Instrument cluster

Speedometer, tachometer, water temperature gauge: 0 displayed

MIL illuminated

ABS warning light illuminated

MULITIPLE COMMUNICATION SYSTEM 

T–11

T

T

Self-Malfunction Diagnostic Function

The self-malfunction diagnostic function determines that there is a malfunction, and outputs a signal, as a DTC, 
to the DLC-2. The DTC can be read out using an SST (WDS or equivalent).

DTC table

PID/Data Monitoring Function

The PID/data monitoring function is used to freely select and read out, in real time, the monitored items for the 
input/output signals of the ABS (ABS/TCS) HU/CM, DSC HU/CM and instrument cluster.

An SST (WDS or equivalent) is used to read out the PID/data monitor information.

Narrowing Down Malfunction Locations

The on-board diagnostic function, by verifying the detected DTC and PID/data monitor information from each 
module, can narrow down a CAN system malfunction location. Refer to the Self-Malfunction Diagnostic 
Function and PID/Data Monitoring Function for detailed information regarding DTCs and the PID/data monitor. 
(See 

T–11 Self-Malfunction Diagnostic Function

.) (See 

T–11 PID/Data Monitoring Function

.)

DTC

Malfunction location

Related module

U0073

CAN system communication error

PCM

U0121

Communication error to ABS (ABS/TCS) HU/CM or DSC HU/CM

U0155

Communication error to instrument cluster

U1900

CAN system communication error

ABS (ABS/TCS) HU/CM
(vehicles with ABS (ABS/TCS))

DSC HU/CM (vehicles with DSC)

Instrument cluster

U2516

CAN system wiring harness open and short circuit

PID name (definition)

Condition

Specification

Related module

Terminal

IC_MSG
(Missing message from the 
instrument cluster)

Present

Circuit in the Instrument cluster 
is normal

ABS (ABS/TCS) 
HU/CM or DSC HU/
CM

ABS (ABS/TCS) 
HU/CM: O, R

DSC HU/CM: AF, 
AG

Instrument cluster: 
2W, 2X

Not Present

Circuit in the Instrument cluster 
is abnormal

ABS_MSG
(Missing message from the 
ABS (ABS/TCS) HU/CM or 
DSC HU/CM)

Present

Circuit in the ABS (ABS/TCS) 
HU/CM or DSC HU/CM is 
normal

Instrument cluster

Not Present

Circuit in the ABS (ABS/TCS) 
HU/CM or DSC HU/CM is 
abnormal

PCM_MSG
(Missing message from the 
PCM)

Present

Circuit in the PCM is normal

ABS (ABS/TCS) 
HU/CM or DSC 
HU/CM

Instrument 
cluster

Not Present

Circuit in the PCM is abnormal

T–12

MULITIPLE COMMUNICATION SYSTEM 

Flowchart

Example (Open circuit in PCM-related wiring harness)

.

Note

This example is for vehicles not equipped with a TCS or DSC.

1. DTCs for the PCM, ABS HU/CM and instrument cluster can be verified using a SST (WDS or equivalent).

A6E8111TH01

A6E8111T008

1

Instrument cluster

2

Circuit open

3

Twist  pair

Module

Displayed DTC

Probable malfunction location

PCM

U0073

PCM-related CAN system malfunction

U0121

Communication error between PCM and ABS HU/CM

U0155

Communication error between PCM and instrument cluster 

ABS HU/CM

U1900, U2516

ABS HU/CM-related CAN system malfunction

Instrument cluster

U1900, U2516

Instrument cluster-related CAN system malfunction

 

 

 

 

 

 

 

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