ELECTRIC PARKING BRAKE [(E)]
id0412007008x2
Outline
• By operating the electric parking brake switch located on the upper panel, the electric parking brake is applied/released electronically.
• Secure holding force with minimum operation of the electric parking brake switch has been realized by motorizing the parking brake.
• With the addition of an electric parking brake automatic release function by the accelerator pedal operation, forgetting to release the parking brake before driving is prevented.
• Because the parking brake has been motorized, adjustment is unnecessary.
• The electric parking brake control module which controls the electric parking brake is located inside the electronically controlled brake unit.
Function
Electric parking brake operation/ release
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• The operation/ release of the electric parking brake is performed based on the signal input from the electric parking brake switch.
Electric parking brake automatic release function
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• Releases the electric parking brake automatically when the vehicle starts from a standstill.
Emergency braking function
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• The function generates braking force by pulling up the electric parking brake switch while the vehicle is driven.
• When the electric parking brake switch is pulled up while the vehicle is driven, the electronically controlled brake unit pressurizes the brake fluid to generate braking force. If a malfunction occurs in the DSC system and the brake fluid cannot be pressurized, the electric parking brake operates to generate braking force.
Electric parking brake automatic operation function
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• Operates the electric parking brake automatically when the main power is switched OFF.
Electric parking brake automatic operation function (during AUTOHOLD operation)
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• Operates the electric parking brake automatically based on the electronically controlled brake unit request during AUTOHOLD operation.
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Note
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• The electric parking brake automatic release function is used to release the electric parking brake during AUTOHOLD operation.
Electric parking brake display function
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• The electronically controlled brake unit notifies the driver of the system conditions using the electric parking brake indicator light, electric parking brake warning chime, center display, and multi-information display.
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Note
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• A warning message on the center display is displayed at the same time the brake control system warning light/electric parking brake indicator light turns on or flashes. For the message content and verification method, refer to [CENTER DISPLAY] in the workshop manual.
Maintenance mode
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• By switching to the maintenance mode when replacing the rear disc pads or rear disc plates, the electric parking brake motor gear unit motor will operate to allow the brake pistons to be pressed in. For details on the method for switching to the maintenance mode, refer to the [MAINTENANCE MODE] in the workshop manual.
Electric parking brake inspection mode
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• The electric parking brake inspection mode is a function that prevents the vehicle from suddenly flying off the brake tester by gradually strengthening the clamp power of the parking brake when the rear wheel speed is between 3—12 km/h {2.0—7.4 mph} for a continuous 3 s or more while using a brake tester with rollers that have a fast rotation speed. When all the operation conditions are met, the normal mode switches to the electric parking brake inspection mode automatically. In addition, normal electric parking brake control is performed when using a brake tester with a rear wheel speed of less than 3 km/h {2 mph}. For details on the operation conditions and the control content, refer to [INSPECTION/SERVICE CAUTIONS] in the Workshop Manual.
Automatic configuration function
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• When the main power is switched ON (READY off or on) after the electronically controlled brake unit has been replaced, the electronically controlled brake unit reads data from the BCM via CAN communication and performs the configuration.
Construction
Block diagram
• The electric parking brake consists of the following parts.
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Part name
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Function
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Electronically controlled brake unit
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Electric parking brake switch
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Electric parking brake motor gear unit
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Electric parking brake indicator light
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Brake control system warning light
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Instrument cluster
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PCM
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BCM
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ABS wheel-speed sensor
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Select lever
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Dash-electrical supply unit
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Door-electrical supply unit
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Operation
Electric parking brake operation
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• The electric parking brake operates when the following operation conditions are met.
Operation conditions
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― Electric parking brake switch is pulled up
― Vehicle is stopped
1. When the electric parking brake switch is pulled up, the electronically controlled brake unit detects an electric parking brake operation request signal (1).
2. When the electronically controlled brake unit detects the electric parking brake operation request signal, it outputs motor operation current (2) to the electric parking brake motor gear unit.
3. The motor operates (3) by the motor operation current. (The motor rotates towards the clamping side)
4. The electric parking brake operates, and the operations stops when the motor reaches the target current.
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Note
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Electric parking brake motor gear unit control contents (when operating electric parking brake)
Electric parking brake release
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• The electric parking brake is released when the electric parking brake switch is pressed with the following operation conditions met.
Operation conditions
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― Main power is switched ON (READY off or on)
― During brake pedal operation or accelerator pedal operation
1. When the electric parking brake switch is pulled up, the electronically controlled brake unit detects an electric parking brake operation request signal (1).
2. The electronically controlled brake unit outputs motor operation current (2) to the electric parking brake motor gear unit.
3. The motor operates (3) by the motor operation current. (The motor rotates in the opposite direction of the clamping side)
4. The electric parking brake is released and when the motor reaches the target stroke, the operation stops.
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Note
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Electric parking brake motor gear unit control contents (when releasing electric parking brake)
Electric parking brake automatic release function
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• The electric parking brake automatic release function operates when the accelerator pedal is depressed with all of the following conditions met.
Operation conditions
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― Main power is switched ON (READY on)
― Driver's door is closed
― Driver seat belt is fastened
― Selector lever is in position other than N or P position
1. When the electronically controlled brake unit receives a signal (1) from the PCM indicating that the accelerator pedal is depressed and a signal (2) indicating that the drive torque necessary for acceleration exceeds the specification, the electric parking brake automatic release function operates and motor operation current (3) flows to the electric parking brake motor gear unit.
2. The motor operates (4) by the motor operation current. (The motor rotates in the opposite direction of the clamping side)
3. The electric parking brake is released and when the motor reaches the target stroke, the operation stops.
Emergency braking function
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Note
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• The emergency braking function operates only when the electric parking brake switch is continuously pulled up while the vehicle is being driven.
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• The emergency brake function operates when all of the following conditions are met.
Operation conditions
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― Vehicle is being driven
― Electric parking brake switch is continuously pulled up
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No malfunction in electronically controlled brake system
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1. When an electric parking brake operation request signal (1) of the electric parking brake switch is detected while the vehicle is being driven, the electronically controlled brake unit generates the brake fluid pressure.
2. The brake fluid pressure is transmitted to the front brakes and rear brakes to generate braking force.
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Malfunction in electronically controlled brake system
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1. When an electric parking brake operation request signal (1) of the electric parking brake switch is detected while the vehicle is being driven, the electronically controlled brake unit outputs motor operation current (2) to the electric parking brake motor gear unit.
2. The motor operates (3) using the motor operation current and generates braking force. (The motor rotates towards the clamping side)
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Note
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• For vehicle speeds of 5 km/h {3 mph} or more, independent anti-lock control on the left and right is performed so that the rear wheels do not lock-up.
• When the vehicle speed is 3 km/h {2 mph} or less, the emergency braking function does not operate because the system determines that the vehicle is stopped.
• If the ABS control is detected while the emergency braking function is operating, control of the emergency braking function is canceled.
Electric parking brake automatic operation function (during AUTOHOLD operation)
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• The electric parking brake automatic operation function operates when all of the following conditions are met.
Operation conditions
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― During AUTOHOLD operation (See
AUTOHOLD.)
1. The electronically controlled brake unit outputs motor operation current (1) to the electric parking brake motor gear unit.
2. The motor operates (2) by the motor operation current. (The motor rotates towards the clamping side)
3. The electric parking brake operates, and the operations stops when the motor reaches the target current.
Electric parking brake display function
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• The instrument cluster displays as indicated in the table below when the vehicle is under the following conditions.
Electric parking brake display function table
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Status
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Electric parking brake indicator light
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Brake control system warning light
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Multi-information display
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Electric parking brake warning chime
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The electric parking brake is operating while the vehicle is stopped.
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ON
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OFF
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No display
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No sound
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The electric parking brake is released.
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OFF
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OFF
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No display
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No sound
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The electric parking brake switch is pressed without depressing the brake pedal while the vehicle is stopped.
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ON
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OFF
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No sound
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The electric parking brake automatic release function operates during acceleration.
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OFF
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OFF
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No display
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No sound
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The accelerator pedal is depressed when the electric parking brake is operating while the vehicle is stopped. (door opened or driver seat belt unfastened)
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ON*1
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OFF
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No sound
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The electric parking brake is operated while the vehicle is driven.
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Flash
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OFF
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ON
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The electric parking brake switch is operated (pulled/ pressed) while the electric parking brake is malfunctioning.
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OFF*2or ON*3
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ON
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No sound
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There is a malfunction in the parking brake force of the electric parking brake.
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Flash
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Parking brake force is normal but malfunction is occurring in electric parking brake system.
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OFF*2or ON*3
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The mode is switched to the maintenance mode.
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OFF
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No display
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The mode is switched to the electric parking brake inspection mode.
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OFF*2or ON*3
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The electric parking brake cannot be operated because there is a malfunction in the electric parking brake system while the vehicle is stopped.
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OFF*2or ON*3
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ON
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No sound
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*1 :Electric parking brake indicator light flashes if vehicle is driven.
*2 :When releasing electric parking brake.
*3 :When operating electric parking brake.
