ON-BOARD DIAGNOSTIC SYSTEM FUNCTION [ABS]

id0402a7182100


Malfunction Detection Function

•  The malfunction detection function detects malfunctions in the input/output signal system of the ABS HU/CM when the ignition switch is at the ON position.
•  When the ABS HU/CM is started up, the following malfunction detections are performed.
―  The ABS and brake system warning lights illuminate for approx. 3 s when the ignition 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. 10 km/h {6.2 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 CAN_H and CAN_L 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 has been turned 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 and EBD as shown in the fail-safe function table.
Warning
•  If EBD control is suspended the rear wheels could lock-up before the front wheels. If this occurs, the vehicle could swerve and become unstable. Therefore always inspect the system immediately if EBD control is suspended.

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

Brake system warning light (when parking brake is released)

ABS control

EBD control
Power supply system
B1317
Illuminated*1
Illuminated*1
Control disabled*2
Control disabled*2
B1318
ABS HU/CM system
B1342
Illuminated
Illuminated
Control disabled
Control disabled
Brake switch signal system
B1484
Not illuminated
Illuminated*3
Control enabled
Control enabled
ABS HU/CM configuration system
B2477
Flash
Not illuminated
Control disabled
Control enabled
ABS sensor rotor
C1141
Illuminated
Not illuminated
Control disabled
Control enabled
C1142
C1143
C1144
ABS wheel-speed sensor system
C1145
C1148
C1155
C1158
C1165
C1168
C1175
C1178
ABS wheel-speed sensor/ABS sensor rotor systems
C1233
C1234
C1235
C1236
Solenoid valve system
C1194
Illuminated
Illuminated
Control disabled
Control disabled
C1198
C1210
C1214
C1242
C1246
C1250
C1254
Valve relay system
C1186
Illuminated
Illuminated
Control disabled
Control disabled
C1266
Not illuminated
Control enabled
Pump motor, motor relay systems
C1095
Illuminated
Illuminated
Control disabled
Control enabled
C1096
Incorrect ABS HU/CM installed
C1805
Illuminated
Illuminated
Control disabled
Control enabled
CAN communication system
U0073
Not illuminated
Not illuminated
Control enabled
Control enabled
U1900
Abnormal message from PCM
U2023

*1  :If the ignition voltage returns to normal, the light goes out.
*2  :If the ignition voltage returns to normal, control is enabled.
*3  :Vehicles without malfunction warning light. (Applied VIN (assumed): NC18**215550—, NC18**250831—, NC30**202488—, NCA8**251024—