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 table

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

•  The snapshot data stores the currently detected DTC data

PID/data monitor function

•  The PID/data monitor function is used for optionally selecting input/output signal monitor items preset in the DSC HU/CM and reading them out in real-time.

PID/data monitor table

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 modes 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