ABS HU/CM DESCRIPTION
BME041343750T01
• The ABS HU/CM detects wheel-speed and driving condition based on the ABS wheel-speed sensors, and outputs on/off electronic signals to the inlet solenoid valves and outlet solenoid valves to control the following functions.
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- 4-sensor, 3-channel select low control ABS control
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- Electronic Brakeforce Distribution (EBD) control uses a 4 sensor, 4-channel system
• CPU1 and CPU2 in the ABS HU/CM monitor each other for ABS HU/CM safety. The function of CPU1 and CPU2 is as follows.
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- CPU1 controls the ABS operation by activating the pressure and outlet solenoid valves based on the signals from each wheel-speed sensor.
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- CPU2 has a self-diagnosis function that monitors the system operation and input/output signals from CPU1. When CPU2 detects system failure, the watch-dog sends (ABS motor and fail-safe) a signal to turn off the relay (ABS motor and fail-safe). As a result, ABS and EBD operation is stopped and shifts to fail-safe mode.
• The ABS HU/CM constantly calculates the average value of the signals from the front ABS wheel-speed sensors and sends a vehicle speed signal to the instrument cluster.
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- The ABS HU/CM constantly sends the average value of the two sensors on either side. In case a malfunction occurs in one of the sensors, however, the ABS sends a value from only the normal sensor.
Block Diagram
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1
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Battery
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2
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ABS wheel-speed sensor
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3
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Brake switch
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4
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Voltage regulator
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5
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ABS wheel-speed sensor input interface
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6
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Switch input interface
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7
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DTC memory
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8
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CPU1
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9
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CPU2
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10
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Watch-dog
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11
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Warning light drive
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12
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Solenoid drive
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13
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Solenoid monitor
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14
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Motor monitor
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15
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Relay drive
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16
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Solenoid valve
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17
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ABS motor
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18
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ABS relay
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19
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DLC
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20
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BRAKE system warning light
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21
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ABS warning light
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22
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Speed signal output drive
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23
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ABS HU/CM
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24
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ABS CM
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25
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ABS HU
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26
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Instrument cluster (Speedometer)
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27
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DLC-2
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