ON-BOARD DIAGNOSTIC SYSTEM FUNCTION [ANTILOCK BRAKE SYSTEM (ABS)]

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Malfunction Detection Function

•  The malfunction detection function detects malfunctions in the input/output signal system of the ABS HU/CM when the ignition switch or engine switch is at the ON position.
•  When the ABS HU/CM are started up, the following malfunction detections are performed.
―  The ABS warning light illuminate for approx. 3 s when the ignition switch or engine switch is turned to the ON position. At the same time, the fail-safe relay is operated, and the input/output signals of each part is monitored for malfunction diagnosis. After starting to drive, the first time the vehicle speed is approx. 12 km/h {7.5 mph} or more the pump motor is operated and malfunction diagnosis is performed again.
•  When malfunctions are detected, the corresponding lights are illuminated to alert the driver. Using the external tester communication function, DTCs can be output through the KLN of the DLC-2. 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 switch or engine switch has been turned off (LOCK position), even if the malfunctioning signal system has returned to normal.
•  Since the ABS 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.

Fail-safe Function

•  When the malfunction detection function determines a malfunction, each light illuminates to advise the driver. At this time, the fail-safe function controls the ABS as shown in the fail-safe function table.

Fail-safe Function Malfunction Contents

Malfunction location

DTC number

Fail-safe function

Warning light illumination status

Control status

Mazda Modular Diagnostic System (M-MDS) display

ABS warning light

ABS control
Power supply system
B1317
Illuminated*1
Control disabled*2
B1318
ABS HU/CM system
B1342
Illuminated
Control disabled
Brake switch signal system
B1484
Not illuminated
Control enabled
Pump motor, motor relay systems
C1095
Illuminated
Control disabled
C1096
ABS wheel-speed sensor system
C1145
Illuminated
Control disabled
C1155
C1165
C1175
Fail-safe relay system
C1186
Illuminated
Control disabled
Solenoid valve system
C1194
Illuminated
Control disabled
C1198
C1202
C1206
C1210
C1214
ABS wheel-speed sensor (slip monitor) system
C1222
Illuminated
Control disabled
ABS wheel-speed sensor/ABS sensor rotor systems
C1233
Illuminated
Control disabled
C1234
C1235
C1236
Incorrect ABS HU/CM installed
C1414
Illuminated
Control disabled
G sensor system*3
C1730
Illuminated
Control disabled
C1949
C1950

*1  :If the ignition voltage returns to normal, the light goes out.
*2  :If the ignition voltage returns to normal, control is enabled.
*3  :4x2 (high clearance model), 4x4