ELECTRIC PARKING BRAKE
id041200700800
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 ignition 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 sound, 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 the [SERVICE CAUTIONS] in the workshop manual.
Construction
Structure
System wiring diagram
Block diagram
• The electric parking brake consists of the following parts.
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Part name
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Functions
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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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― Pull up the electric parking brake switch.
― The 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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― Ignition switch ON (engine off or on)
― During brake pedal operation or accelerator pedal operation.
1. When the electric parking brake switch is pressed, the electronically controlled brake unit detects an electric parking brake release request signal (1).
2. The electronically controlled brake unit outputs the 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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― Ignition is switched ON (engine on)
― Driver's door closed
― Driver seat belt fastened
― Selector lever is in position other than N and P
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
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• The electric parking brake operates automatically when all of the following conditions are met.
Operation conditions
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― Vehicle is stopped (wheel speed is 3 km/h {2 mph} or less)
― Ignition is switched from ON to OFF*1
― Operation to cancel automatic operation is not performed by driver
*1 :If the ignition is switched from ON to OFF while the vehicle is being driven, such as when performing an emergency engine stop operation, the electric parking brake automatic operation function operates when the vehicle decelerates with the ignition switched OFF and stops.
1. The BCM sends (1) an engine switch signal to the electronically controlled brake unit. When the electronically controlled brake unit detects that the received engine switch signal has switched from ON to OFF, it outputs a motor operation current (2) to the electric parking brake motor gear unit.
2. The motor operates (3) by the motor operation current. (The motor rotates towards the clamping side.)
3. The electric parking brake operates, and the operation stops when the motor reaches the target current.
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Caution
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• When the electric parking brake automatic operation is canceled, shift the selector lever to the P position and set wheel blocks on the tires to prevent the vehicle from moving unexpectedly.
• The electric parking brake automatic operation may not be able to be canceled when the vehicle is on a steep slope.
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• The electric parking brake automatic operation may be canceled by performing any of the following procedures.
Procedure 1
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1. Switch the ignition ON (engine off or on).
2. Release the electric parking brake manually.
3. Switch the AUTOHOLD off.
4. Press the electric parking brake switch down continuously for 2 s or more.*1
5. Release the electric parking brake switch and switch the ignition OFF within 5 s since the electric parking brake warning sound was activated.*2
Procedure 2
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1. Switch the ignition ON (engine off or on).
2. Release the electric parking brake manually.
3. Switch the AUTOHOLD off.
4. With the electric parking brake switch pressed down, switch the ignition OFF without depressing the brake pedal.*2
*1 :When the operation is authorized, the electric parking brake warning sound is activated.
*2 :When the automatic operation cancelation is authorized, the electric parking brake warning sound is activated and the electric parking brake switch indicator light flashes for 3 s and then turns off.
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• When the ignition is switched ON again, the electric parking brake automatic operation returns to normal control.
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 condition
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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 table
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Condition
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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 sound
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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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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
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Off
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No sound*1
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The electric parking brake is operated while the vehicle is driven.
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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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Flash
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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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Parking brake force is normal but malfunction is occurring in electric parking brake system
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Off*2 or 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*2 or 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*2 or on*3
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On
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No sound
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*1 :Activates if the vehicle driven
*2 :When releasing electric parking brake
*3 :When operating electric parking brake
