ON-BOARD DIAGNOSTIC SYSTEM[L3]
id0402a1181300
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 detection operations are performed:
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― The ABS and brake system warning lights illuminate for approx. 3.0 s when the ignition switch is turned to the ON position to inspect for open circuits in the lights. At the same time, the fail-safe relay is operated, and the input/output signals of each part is monitored for malfunction diagnosis. Also, 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. After that, input/output signals are regularly monitored for malfunction determination.
• When malfunctions are detected, the corresponding lights are illuminated to alert the driver. DTCs are output through the CAN_H and CAN_L terminals 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 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 and EBD as shown in the fail-safe function table.
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Warning
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• 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
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Malfunction location
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DTC
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Fail-safe function
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Warning light illumination status
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Control status
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Mazda Modular Diagnostic System (M-MDS) display
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ABS warning light
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Brake system warning light (when parking brake is released)
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ABS control
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EBD control
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ABS HU/CM
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B1342
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Illuminated
|
Illuminated
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Disabled
|
Disabled
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Power supply system
|
B1676
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Illuminated
|
Illuminated
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Disabled
|
Disabled
|
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Not illuminated *1
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Enabled*1
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ABS HU/CM configuration system
|
B2477
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Illuminated
|
Not illuminated
|
Disabled
|
Enabled
|
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PCM communication
|
B2900
|
Illuminated
|
Not illuminated
|
Disabled
|
Enabled
|
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Pump motor, motor relay
|
C1095
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Illuminated
|
Not illuminated
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Disabled
|
Enabled
|
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ABS wheel-speed sensor
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C1145
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Illuminated
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Not illuminated *2
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Disabled
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Enabled*3
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C1155
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C1165
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C1175
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LF ABS sensor rotor
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C1233
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Illuminated
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Not illuminated *2
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Disabled
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Enabled*3
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C1234
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C1235
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C1236
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G-sensor
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C1730
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Illuminated
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Not illuminated
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Disabled
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Enabled
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PCM communication
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C1805
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Illuminated
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Not illuminated
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Disabled
|
Enabled
|
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G-sensor
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C2769
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Illuminated
|
Not illuminated
|
Disabled
|
Enabled
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C2770
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CAN line
|
U1900
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Not illuminated *4
|
Not illuminated *4
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Enabled
|
Enabled
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U2023
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*1 :Detected if condition of 9.7 V±0.3 V or less continues for 210 ms or more.
*2 :Illuminates when two wheels or more have a malfunction.
*3 :Control disabled when two wheels or more have a malfunction.
*4 :Illuminates depending on malfunction contents.