ELECTRIC PARKING BRAKE

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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, forgetting to release the parking brake before driving is prevented by depressing the accelerator pedal.
•  Because the parking brake has been motorized, adjustment is unnecessary.

Functions


Electric parking brake operation/release

•  Controls the operation/release of the electric parking brake based on the input signal from the electric parking brake switch and the CAN-related module communication data.


Electric parking brake automatic release function

•  Releases the electric parking brake automatically when the vehicle starts from a standstill.


Emergency braking function

•  The electric parking brake can be applied while driving the vehicle. Braking force is generated and the rear wheels are controlled so that they do not lock-up only when the electric parking brake is pulled up while the vehicle is being driven.


Electric parking brake automatic operation function (during AUTOHOLD operation) (With AUTOHOLD)

•  The electric parking brake operates automatically based on the DSC HU/CM request during AUTOHOLD operation.
Note
•  The electric parking brake automatic release function is used to release the electric parking brake during AUTOHOLD operation.


Electric parking brake automatic operation function (when electric parking brake switch is malfunctioning)

•  If the electric parking brake switch is malfunctioning, the electric parking brake operates automatically.
Note
•  If the electric parking brake switch is malfunctioning, the electric parking brake automatic release is used to release the electric parking brake.


Electric parking brake display function

•  The electric parking brake control module notifies the driver of the system conditions using a electric parking brake indicator light, electric parking brake warning light, brake pedal operation demand indicator light (green)*1, electric parking brake chime, center display, and multi-information display*2.
*1   :Vehicles without multi-information display
*2   :Vehicles with multi-information display
Note
•  For vehicles with the center display, a warning message in the center display is displayed when the electric parking brake warning light/electric parking brake indicator light turns on or flashes. For the message content and verification method, refer to the [CENTER DISPLAY]. (See CENTER DISPLAY.)


Maintenance mode

•  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

•  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 2.5 km/h {1.6 mph} and 9.0 km/h {5.5 mph} 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 2.5 km/h {1.5 mph}. For details on the operation conditions and the control content, refer to the [SERVICE CAUTIONS] in the Workshop Manual.


Automatic configuration function

•  When the ignition is switched ON after the electric brake control module has been replaced, the electric brake control module reads the data from the instrument cluster via CAN communication and performs the configuration.


Construction

Structure

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System wiring diagram

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*   :For details on other CAN related modules, refer to the [MULTIPLEX COMMUNICATION SYSTEM]. (See MULTIPLEX COMMUNICATION SYSTEM.)

Block diagram

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•  The electric parking brake consists of the following parts.

Part name

Functions
Electric parking brake control module
(See ELECTRIC PARKING BRAKE CONTROL MODULE.)
DSC HU/CM
•  Transmits information such as brake hydraulic pressure or wheel speed to the electric parking brake control module via CAN communication.
PCM
•  Transmits information such as the accelerator pedal depression amount and engine speed to the electric parking brake control module via CAN communication.
TCM
(See TCM.)
SAS control module
(See SAS CONTROL MODULE.)
Instrument cluster
(See INSTRUMENT CLUSTER.)
Electric parking brake switch
(See ELECTRIC PARKING BRAKE SWITCH.)
Electric parking brake motor gear unit
(See ELECTRIC PARKING BRAKE MOTOR GEAR UNIT.)
Electric parking brake indicator light
(See ELECTRIC PARKING BRAKE INDICATOR LIGHT, ELECTRIC PARKING BRAKE WARNING LIGHT.)
Electric parking brake warning light
(See ELECTRIC PARKING BRAKE INDICATOR LIGHT, ELECTRIC PARKING BRAKE WARNING LIGHT.)
Brake pedal operation demand indicator light (green)*
(See BRAKE PEDAL OPERATION DEMAND INDICATOR LIGHT (GREEN).)

*   :Vehicles without multi-information display

Operation


Electric parking brake operation

•  The electric parking brake operates when the following operation conditions are met.
Operation condition
―  Pull up the electric parking brake switch.

1.  When the electric parking brake switch is pulled up, the electric parking brake control module detects an electric parking brake operation request signal (1).

2.  When the electric parking brake control module 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 engagement side)

4.  The electric parking brake operates, and the operations stops when the motor reaches the target current.

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Note
Electric parking brake motor gear unit control contents (when operating electric parking brake)
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Electric parking brake release

•  The electric parking brake is released when the electric parking brake switch is pressed with the following operation conditions met.
Operation condition
―  Ignition switch ON (engine off or on)
―  Brake pedal is being operated, accelerator pedal is being operated, or vehicle is being driven

1.  When the electric parking brake switch is pressed, the electric parking brake control module detects an electric parking brake release request signal (1).

2.  The electric parking brake control module 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 engagement side)

4.  The electric parking brake is released and when the motor reaches the target stroke, the operation stops.

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Note
Electric parking brake motor gear unit control contents (when releasing electric parking brake)
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Electric parking brake automatic release function

•  The electric parking brake automatic release function operates when the accelerator pedal is depressed with all of the following conditions met.
Operation condition
―  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.  The electric parking brake automatic release function activates and motor operation current (3) flows to the electric parking brake motor gear unit when the electric parking brake control unit receives a signal (1) from the PCM indicating that the accelerator pedal is depressed and a signal (2) indicating that the drive toque necessary for acceleration exceeds the specification.

2.  The motor operates (4) by the motor operation current. (The motor rotates in the opposite direction of the engagement side)

3.  The electric parking brake is released and when the motor reaches the target stroke, the operation stops.

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Emergency braking function

Note
•  The emergency braking function operates only when the electric parking brake switch is continuously pulled up while the vehicle is being driven.
•  If the accelerator pedal is depressed while the emergency brake function is operating, the emergency brake is released to give priority to vehicle acceleration.
•  The emergency brake function operates when all of the following conditions are met.
Operation condition
―  Vehicle is being driven
―  Electric parking brake switch is continuously pulled up

1.  When the electric parking brake control module detects an electric parking brake operation request signal (1) of the electric parking brake switch while the vehicle is being driven, it sends motor operation current (2) to the electric parking brake motor gear unit.

2.  The motor operates (3) and generates braking force by the motor operation current. (The motor rotates towards the engagement side)

Note
•  For vehicle speeds of 7 km/h {4 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 6 km/h {4 mph} or less, the emergency braking function does not operate so that the system can determine if the vehicle is about to stop.
•  If the ABS control is detected while the emergency braking function is operating, control of the emergency braking function is canceled.
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Electric parking brake automatic operation function (during AUTOHOLD operation) (With AUTOHOLD)

•  The electric parking brake automatic operation function operates when all of the following conditions are met.
Operation condition
―  During AUTOHOLD operation
―  The electric parking brake control module receives an electric parking brake operation request signal from the DSC HU/CM. (See DYNAMIC STABILITY CONTROL (DSC).)

1.  When the electric parking brake control module receives a electric parking brake operation request signal (1) from the DSC HU/CM, the electric parking brake automatic operation function is operated to output 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 engagement side)

3.  The electric parking brake operates, and the operations stops when the motor reaches the target current.

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Electric parking brake automatic operation function (when electric parking brake switch is malfunctioning)

•  The electric parking brake automatic operation function operates when all of the following conditions are met.
Operation conditions (ignition switched OFF)
―  Electric parking brake switch malfunction signal
―  Ignition is switched OFF
―  Brake pedal is depressed or driver's door is open
Operation conditions (ignition is switched ON (engine off or on))
―  Electric parking brake switch malfunction signal
―  Ignition is switched ON (engine off or on)
―  Selector lever is in N or P position
―  Driver's door is closed from open condition

1.  When all of the operation conditions of the electric parking brake automatic operation function are met, the electric parking brake automatic operation function operates and the electric parking brake control module sends 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 engagement side)

3.  The electric parking brake operates, and the operation stops when the motor reaches the target current.

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Electric parking brake display function

•  The instrument cluster displays as indicated in the table below when the vehicle is under the following conditions.
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Electric parking brake display table

Condition

Electric parking brake indicator light

Electric parking brake warning light

Brake pedal operation demand indicator light (green)*1

Multi-information display*2

Electric parking brake chime
The electric parking brake is operating while the vehicle is stopped.
On
Off
Off
No display
Off
Electric parking brake is released.
Off
Off
Off
No display
Off
The electric parking brake switch is pressed without depressing the brake pedal while the vehicle is stopped.
On
Off
On
Off
The electric parking brake automatic release function operates during acceleration.
Off
Off
Off
No display
Off
The accelerator pedal is depressed when the electric parking brake is operating while the vehicle is stopped (door opened or driver seat belt unfastened)
On
Off
Off
Off*3
The electric parking brake is operated while the vehicle is driven.
On
Electric parking brake switch or electric parking brake motor gear unit malfunction affects parking brake force of electric parking brake
Flash
On
Off
No display
Off
No malfunction in parking brake force, but malfunction occurring in electric parking brake system
Off*4 or on*5
The mode is switched to the maintenance mode.
Off
The mode is switched to the electric parking brake inspection mode.
Off*4 or on*5
Operation is limited by continuous operation of the electric parking brake.
Off
On
Off
Off
The electric parking brake cannot be operated because there is a malfunction in the electric parking brake system while the vehicle is stopped.
Off*4 or on*5

*1   :Without multi-information display
*2   :With multi-information display
*3   :Activates if the vehicle is driven.
*4   :When releasing electric parking brake
*5   :When operating electric parking brake