ON-BOARD DIAGNOSTIC SYSTEM [DYNAMIC STABILITY CONTROL (DSC)]

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OUTLINE

Block diagram

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FUNCTION

Malfunction detection function

•  The malfunction detection function detects and displays malfunctions in the input/output signal system of the DSC HU/CM when the ignition is switched to ON.

•  When the DSC HU/CM is activated, the following malfunction detection is performed.

―  The ABS warning light, brake system warning light, TCS/DSC indicator light, TSC OFF indicator light, tire pressure monitoring system warning light and master warning light illuminate for approx. 3.0 s when the ignition is switched to ON to inspect for open circuits in the lights. At the same time, the input/output signals of each part is monitored for malfunction diagnosis. After starting to drive, the first time the vehicle speed is approx. 10 km/h {6.2 mph} or more the pump motor is operated and malfunction diagnosis is performed again. The input/output signals of each part are then constantly monitored and malfunctions are diagnosed.

Note

•  When the pump motor operates, it is sound can be heard.

•  If the above malfunctions are detected, the corresponding lights are illuminated to alert the driver. DTCs can be output through the CAN_H and CAN_L of the DLC-2 using the external tester communication function. At the same time, malfunction detection results are sent to the memory and fail-safe functions.

Memory function

•  The memory function stores DTCs of malfunctions in input/output signal systems. With this function, once a DTC is stored it is not cleared after the ignition has been switched off, even if the malfunctioning signal system has returned to normal.

•  Since the DSC HU/CM has a built-in non-volatile memory, DTCs are not cleared even if the battery is removed. Therefore, it is necessary to clear the memory after performing repairs. Refer to the Workshop Manual for the DTC clearing procedure.

DTC 7-digit code definition

•  When related systems or components have failed, the CM stores the DTC of the malfunctioning part in the CM memory, and allows for the retrieval of the store data using scanning tool when necessary. The DTCs are indicated using seven digits. Each digit indicates the following.

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Fail-safe function

•  When the malfunction detection function determines a malfunction, the warning indicator light illuminates to alert the driver. At this time, the fail-safe function controls as indicated in the fail-safe function malfunction contents table.

Warning

•  If EBD control is prohibited, the rear wheels could lock-up before the front wheels. If this occurs, the vehicle could yaw and become unstable. Therefore, always inspect the system immediately if EBD control is prohibited.

Fail-safe Function Malfunction Contents

Status byte for DTC

•  The status byte is the two-digit code (two digits after hyphen (-)) after the DTC.

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•  The status byte is a code which indicates the pending code, current/past malfunction status, or warning illumination status.

•  The status byte can be read by performing a CMDTC self test using the Mazda Modular Diagnostic System (M-MDS).

•  For details on the status byte, refer to the explanation on the Mazda Modular Diagnostic System (M-MDS) when reading the DTC.

Snapshot data

Note

•  The EPS CM stores the following two types of information when a DTC is detected and displays snap shot data in the M-MDS.

―  Vehicle information detected by EPS CM

―  Vehicle information detected by instrument cluster and received by start stop unit via CAN signal

•  The snapshot data stores the currently detected DTC data

Snapshot data item	Unit	Data contents	Data read/use method	Corresponding data monitor items
AAT	°C, °F	Ambient air temperature	Not applicable.	Not applicable.
ABS	Inactive/ Active	Antilock braking system	Not applicable.	Not applicable.
APP_STATUS	Accelerator Pedal Off/ Under 20%/ Over 20%/ FAIL	Accelerator pedal position	Not applicable.	Not applicable.
AYC	Inactive/ Active	Active yaw control	Not applicable.	Not applicable.
BRK_F_P_R	Pa, psi	Brake fluid line hydraulic pressure (Raw Value)	BRK_F_P_R	BRK_F_P_R
BTCS	Inactive/ Active	Brake traction control system	Not applicable.	Not applicable.
CFG_STATUS	Config Complete/ Not Configured/ Config Error	Instrument cluster configuration status	Not applicable.	Not applicable.
ECT_STATUS	Under 0 degrees C/ 0 - Under 80 degrees C/ Over 80 degrees C/ FAIL	Engine coolant temperature status	Not applicable.	Not applicable.
EDC	Inactive/ Active	Engine drag control	Not applicable.	Not applicable.
IC_VPWR	V	Instrument cluster power supply	•  The DSC HU/CM constantly receives the power supply voltage value of the instrument cluster sent via CAN signal from the instrument cluster. •  If a DTC is detected, the DSC HU/CM records the power supply voltage of the instrument cluster when the DTC was detected, and it is displayed in the M-MDS.	VRWR*2
IG-ON_TIMER	hh:mm:ss*1	Elapsed time since ignition was switched ON Note •  The instrument cluster records the elapsed time since the ignition was switched ON.	•  The DSC HU/CM constantly receives the elapsed time since the ignition was switched ON sent via CAN signal from the instrument cluster. •  If a DTC is detected, the DSC HU/CM records the elapsed time since the ignition was switched ON when the DTC was detected, and it is displayed in the M-MDS.	Not applicable.
LAT_ACCL_R	G	Lateral acceleration (Raw Value)	LAT_ACCL_R	LAT_ACCL_R
LON_ACCL_R	G	Longitudinal acceleration (Raw Value)	LON_ACCL_R	LON_ACCL_R
PMP_MT	Off/On	Pump motor	Not applicable.	Not applicable.
PWR_MODE_KEY	Key Out/ Key Recently Out/ Key Approved(Position 0)/ Post Accessory (Position 0)/ Accessory (Position 1)/ Post Ignition (Position 1)/ Ignition On (Position 2)/ Running (Position 2)/ Running - Starting In Progress (Position 2)/ Crank (Position 3)	•  Key Out: Ignition switched to off •  Key Recently Out (Position 0): Elapsed time within 3 s since ignition was switched to off •  Accessory (Position 1): Ignition is switched to ACC •  Post Ignition (Position 2): Elapsed time within 3 s since ignition was switched ON •  Ignition On (Position 2): Ignition switched ON (engine off) •  Running (Position 2): Ignition switched ON (engine on) •  Running - Starting: Cranking condition	•  The DSC HU/CM constantly receives the ignition switch status sent via CAN signal from the instrument cluster. •  If a DTC is detected, the DSC HU/CM records the ignition switch status when the DTC was detected, and it is displayed in the M-MDS.	Not applicable.
RPM_STATUS	Engine Stop/ Under 1500rpm/ Over 1500rpm/ FAIL	Engine RPM status	•  The DSC HU/CM constantly receives the ignition switch status sent via CAN signal from the instrument cluster. •  If a DTC is detected, the DSC HU/CM records the ignition switch status when the DTC was detected, and it is displayed in the M-MDS.	TACHOMTR*2
SHIFT_STATUS	P/N D/ R/ FAIL	Shift position status	•  The DSC HU/CM constantly receives the selector lever position sent via CAN signal from the instrument cluster. •  If a DTC is detected, the DSC HU/CM records the selector lever position when the DTC was detected, and it is displayed in the M-MDS.	Not applicable.
STR_ANG_C	°	Steering wheel angle (Calculated Value)	STR_ANG_C	STR_ANG_C
TCS	Inactive/ Active	Traction control system	Not applicable.	Not applicable.
TOTAL_DIST	km, ft, mi	Accumulated total traveled distance from completion of vehicle until DSC HU/CM detects DTC (Odometer value in instrument cluster)	The distance traveled when the DSC HU/CM detected a DTC can be calculated by performing the following procedure. 1.  Verify the odometer value in the instrument cluster. 2.  Verify the snap shot data item TOTAL_DIST. 3.  Subtract 2 from 1.	Not applicable.
TOTAL_TIME	hh:mm:ss*1	Accumulated total elapsed time since vehicle completion until DSC HU/CM detects a DTC Note •  When the ROOM removed, and the ignition is switched to off, the time is not included in the elapsed time.	The elapsed time when the DSC HU/CM detected a DTC can be calculated by performing the following procedure. 1.  Verify the PID item TOTAL_TIME of the instrument cluster. 2.  Verify the snap shot data item TOTAL_TIME. 3.  Subtract 2 from 1.	Not applicable.
VPWR	V	Power supply	VPWR	VPWR
VSPD	KPH, MPH	Vehicle speed	VSPD	VSPD
VSPD_STATUS	Stop/ 0 - 10km/h/ Over 10km/h/ FAIL	When a DTC is detected, the DSC HU/CM receives the vehicle speed being detected by the instrument cluster via CAN signals and displays it in the M-MDS.	•  The DSC HU/CM constantly receives the vehicle speed sent via CAN signal from the instrument cluster. •  If a DTC is detected, the DSC HU/CM records the vehicle speed when the DTC was detected, and it is displayed in the M-MDS.	SPEEDOMTR*2
YAW_RATE_R	°/S	Yaw Rate (Raw Value)	YAW_RATE_R	YAW_RATE_R

Active command modes function

•  The active command modes function is used for optionally selecting simulation items of input/output parts preset in the DSC HU/CM, and to operate them regardless of CM control.

•  To protect the hydraulic unit interior, operate output related parts for only 2 s or less when using the active command modes function.

Active command mode table

External tester communication function

•  The external tester communication function enables communication of diagnostic data (DTC read-outs, input/output signal read-outs, operation of input/output parts) between the DSC HU/CM and an external tester.

Connections/communication contents

Serial communication

•  Serial communication (two-way communication) allows for multiple data to be sent and received instantly along the same line.

•  By connecting the Mazda Modular Diagnostic System (M-MDS) to the DLC-2, diagnostic data can be sent and received between the Mazda Modular Diagnostic System (M-MDS) and the DSC HU/CM using the CAN_H and CAN_L terminals (within the DLC-2).

•  The DSC HU/CM receives the command signals of the malfunction detection function, PID/data monitor function, and the active command modes function based on the Mazda Modular Diagnostic System (M-MDS), and sends DTCs and data regarding the operating condition and status of each input/output part to the Mazda Modular Diagnostic System (M-MDS).

Diagnostic function name	Signal received	Signal sent
Malfunction detection function	DTC verification signal	DTC
PID/data monitor function	Command signal to read selected monitor item	Monitored data for requested monitor item
Active command modes function	Operation command signal for selected active command modes item	Output part drive signal