Honda HR-V: Description

ELECTRIC PARKING BRAKE SYSTEM DESCRIPTION - CLUTCH PEDAL STROKE SENSOR

The clutch pedal stroke sensor is located in the clutch pedal bracket. The clutch pedal stroke sensor detects the level of clutch pedal force and outputs two kinds of voltage values depending on the given angle.

For M/T vehicles, the clutch pedal stroke sensor determines the clutch engagement status, the back-up light switch determines if gear is in forward or reverse, and the neutral position sensor determines if the gear is engaged. Based on these inputs, the electric parking brake system adjusts the engine torque according to the road gradient and the clutch engagement point to set the timing to cancel the electric parking brake. The electric parking brake control unit sends the clutch pedal stroke sensor value to the PCM via F-CAN. Since the electric parking brake control unit is equipped with the clutch pedal stroke sensor, it has the following learning values, which are obtained by its auto learning functions: The electric parking brake control unit detects the longitudinal g-force that is created when the clutch is engaged every time the vehicle starts moving on level ground in order to determine that the clutch is engaged and then to correct the engagement point information. The learning value is updated every time the vehicle starts moving on level ground.

To correct variances in output values among clutch stroke sensors, the electric parking brake control unit identifies the at rest and fully-pressed positions of the clutch pedal to keep voltages updated with corrected ones.

ELECTRIC PARKING BRAKE SYSTEM DESCRIPTION - CONTROL

Electric Parking Brake Operation-Using Switch

The electric parking brake can be manually applied and released using the switch. Pulling up on the electric parking brake switch applies the parking brake. Firmly applying the brake pedal and pushing down on the electric parking brake switch releases it.

Applying parking brake

Releasing parking brake

Electric Parking Brake Automatic Operation-Drive Away Assist (With M/T model)

The electric parking brake is released automatically when the vehicle is driven away from a stop with the engine running, the vehicle in gear, the clutch engaged, and the driver's seat belt buckled. When the electric parking brake control unit confirms the appropriate amount of engine torque to move the vehicle forward relative to the incline of the slope, the electric parking brake releases.

Electric Parking Brake Automatic Operation-Drive Away Assist (Without M/T model)

The electric parking brake is released automatically when the vehicle is driven away from a stop with the driver's seat belt buckled. Problems in the electric parking brake switch circuits do not affect automatic apply and release.

Electric Parking Brake Automatic Operation-Request From VSA Modulator-Control Unit

When the automatic brake hold control by the VSA system lasts for more than about 10 minutes, the VSA automatically activates the electric parking brake system.

High Temperature Reclamp Function

Brake rotor temperature is calculated from the vehicle's kinetic energy as it stops, because loss of clamping force can occur when brake system components contract as they cool. If the calculated brake temperature exceeds a predetermined threshold, the high temperature reclamp function reapplies the electric parking brake actuators after a cool-down time has elapsed to compensate for any loss of clamping force. In order to accommodate this function, the electric parking brake control unit, VSA modulator-control unit, and F-CAN bus may be kept awake for a period of time after the vehicle is switched to the OFF (LOCK) mode. Depending on when the high temperature reclamp occurs, the driver may notice the motor noise.

Roll-Away Reclamp Function

The roll-away reclamp function reapplies the parking brake if wheel movement is detected after the electric parking brake is applied.

Reduced Clamp Force Function

To shorten operating time and reduce a dragging feeling at the start, the actuators can apply full or reduced clamping force, depending on the grade where the vehicle is parked.

Brake Pad Maintenance Mode

The electric parking brake system has a brake pad maintenance mode functional test. This test fully releases the parking brake mechanism so that brake service, such as rear pad replacement, can be done. Brake pad maintenance mode can be activated by the HDS.

If the electric parking brake switch failure is observed, turn the vehicle to the OFF (LOCK) mode to apply the electric parking brake. In this case, cancel the electric parking brake by pressing the accelerator pedal.

ELECTRIC PARKING BRAKE SYSTEM DESCRIPTION - ELECTRIC PARKING BRAKE ACTUATOR

The electric parking brake actuator has a built-in DC motor. When the motor operates, the motor's speed is reduced by a drive belt and a 2 step gear set to increase the torque. The output wheel then turns a threaded spindle and lock nut inside the caliper piston, forcing it outward to generate the brake pad clamping force. The electric parking brake actuators are automatically adjusted to compensate for brake pad wear, so no parking brake adjustment is necessary.

When the electric parking brake system has a malfunction and the parking brake does not release, use the forced cancellation procedure to release the parking brake. Refer to the shop manual for details about the forced cancellation procedure.

Actuator Control

To activate the parking brake, the control unit drives the relay H bridge circuit and it provides 12-volt power and ground to the motors located in each rear brake actuator. The current flow in the circuit is then reversed to release the parking brake. When the actuators are applying or releasing, the driver may notice the motor noise and feel a slight movement in the brake pedal.

ELECTRIC PARKING BRAKE SYSTEM DESCRIPTION - ELECTRIC PARKING BRAKE SWITCH

The electric parking brake switch is connected to the electric parking brake control unit using four separate low-voltage circuits. The diodes inside the switch alter the current flow to change the individual circuit voltages in each switch position. The control unit must see the correct voltage patterns on all 4 circuits, or the switch will be disabled and a DTC will be set.

ELECTRIC PARKING BRAKE SYSTEM DESCRIPTION - OVERVIEW

The electric parking brake system replaces the traditional parking brake pedal or lever and linkage with an electrically controlled parking brake mechanism in the rear calipers.This reduces driver effort and provides additional features such as:

• Simple electric switch operation
• Parking brake release upon acceleration
• Automatic rollaway prevention

The electric parking brake consists of the following primary components:

• Electric parking brake control unit (with a built-in longitudinal acceleration sensor)
• Electric parking brake actuators
• Electric parking brake switch

ELECTRIC PARKING BRAKE SYSTEM DESCRIPTION - SYSTEM DIAGRAM

This system diagram shows the inputs and outputs of the electric parking brake system.

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