Front Doorslink
Last updated: January 09, 2024
Overviewlink
The purpose of the power front door is to allow for more usability and comfort in entering and leaving the vehicle than any existing door. The door operation has the ability to work with 100% electrical operation, including all latches and movement actuation. The power front door system is comprised of a standard door mounted on free-moving hinges, powered by an electric DC motor (actuator). There is an exterior door push handle that is pressed to command the door to open from outside of the vehicle. There is a standard interior mechanical release to unlatch the door from inside the vehicle.
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| 1. Exterior door handle switch assembly 2. Door push actuator (ice-breaker) 3. Electronic latch and striker 4. Front door pinch strip sensor (not used, only installed on first 2015 Model X) 5. Front door actuator (drive unit) 6. Front door controller (BCFDM/BCFPM) |
| Main Components Inside the Front Door |
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| Schematic Overview of the Front Door Components |
Note
With the introduction of the 2nd generation door latches, the pinch strip sensors are not longer installed.
Componentslink
Drive unit (actuator)link
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| 1. Door linkage 2. Reduction gears 3. Electromechanical brake 4. Planetary gear assembly 5. DC motor 6. Motor encoder |
| Drive Unit Actuator |
The front door actuator uses an electric motor to drive a system of gears that rotate a linkage to open and close the front door. An integrated electromechanical brake prevents and slows rotation of the linkage.
The front door actuator brake is a normally closed electromechanical brake operated by a pulse width modulation (PWM) signal from the corresponding front door control module to control brake force dependent on external force, incline, decline, tilt, and calibration data. A brake auto-calibration function managed by the front door controller is used to compensate for brake wear over time.
Exterior door handlelink
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| 1. Rubber weather seal 2. Bezel 3. Micro switch (inside) |
| Door Handle Assembly |
The exterior door handle assembly has an integrated microswitch that is actuated upon the door handle being pressed. There is a spring mechanism that is designed to return the handle to the un-pressed position immediately upon release. The door handle chrome bezel is replaceable and alignment is adjustable from adjustment screws behind the assembly and bezel.
Interior door handlelink
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| Interior Door Handle |
To operate the interior door handles, pull the lever. The front door interior release handles have a switch that is pressed when the handle is pulled. This sends a signal to the door control module to request the door to unlatch and open. The interior door handle is also mechanically connected to the door latch via a release cable. If the switch fails or there is a power failure, the release cable acts as a mechanical backup and releases the latch.
Front door controllerlink
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| 1. Heat sink plate 2. Control module |
| Front Door Controller |
The Front Door Controller (BCFDM/BCFPM) is an electronic control unit that takes input from sensors and gives output to the drive unit and latch, dictating the motion of the door by inputting sensor values into programmed algorithms. There is one module for each front door which controls the respective front door side mirrors, window regulator, door actuator, latch, and ice-breaker actuator. The left and right front door controllers are the same except for the heat sink plates which are not interchangeable, therefore they have unique part numbers. Because the front door controllers are identical in terms of electronics, they need to know which door they are mounted to. This is done via 2 pins on each of the door modules. These pins are called 'Door ID 1' and 'Door ID 2' in the wiring diagram. One of the Door ID pins is connected to ground and the other is left open. The combination of Door IDs tell the door modules at which side they are mounted. An issue with any of these 4 pins can make the controller think it is mounted on another door, which can cause unexpected behavior with the doors.
| Door ID 1 | Door ID 2 | |
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| Front door controller - left | Ground | Open |
| Front door controller - right | Open | Ground |
Pinch sensorlink
Note
With the introduction of the 2nd generation door latches, the pinch strip sensors are not longer installed.
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| Pinch Strip Sensor Assembly |
The pinch sensor is composed of electrically conductive layers, with the contacts inside a rubber profile. When in neutral position, the contacts are separated from each other by means of an insulating layer. Whenever pressure is applied during the closing operation, the conductive layers are pressed onto each other. This triggers a signal to the corresponding front door module and the door closing operation is electronically stopped by the door control module.
Ice breakerlink
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| Ice Breaker Actuator |
An electronic actuator that extends to apply force against the body B-pillar to push the door open in the case that the door frozen shut. The actuator is controlled by the corresponding front door control module using a 9V pulse width modulation (PWM) signal.
Electronic cinching door latchlink
The front door latches are located inside each door. The latch is primarily electric, but a cable is connected to the latch from the front door interior release handle to open the door in case there is an electrical fault or failure.
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| Cinching Door Latch |
1st generation door latcheslink
Vehicles built before or on 8-MAY-2017 are built with 1st generation door latches. 1st generation front door latches house all components in a single assembly. The assembly is comprised of a motor, a set of gears, various mechanical links and 2 position sensors that report to the driver the state of the mechanism at all times. It reports if the door is open, latched (primary latch position) or ajar (secondary latch position). 1st generation front door latches are controlled by the corresponding front door controllers on a 19.2k LIN network channel. This is also used for reprogramming of the latch firmware.
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| 1. 1st generation front door latch |
2nd generation door latcheslink
Vehicles built after 8-MAY-2017 are built with 2nd generation door latches. 2nd generation front door latches have the cinch motor external to the latch assembly. Despite the cinch motor being external to the door latch, it is part of the latch assembly and therefore is non-serviceable. The release motor is also external to the door latch but is a serviceable component. All other components such as gears, linkages, and the 2 position sensors are part of the latch assembly. 2nd generation front door latches are not controlled over LIN but instead are controlled directly by the corresponding door controllers.
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| 2nd generation front door latch assembly |
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| 1. Front door latch 2. Cinch motor 3. Manual release cable 4. Release motor |
| 2nd generatior door latch assembly |
Replacing Model X doors and front door latcheslink
1st generation door latches are no longer being produced and cannot be ordered. When replacing a 1st generation front door or door latch, order and install the 2nd generation parts. For more information on this upgrade, refer to Collision Repair Procedure Front Door and Front Door Latch Replacement.
Door latch strikerlink
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| Front Door Striker |
The front door latch striker is located on the ‘B’ pillar. The latch strikers can be adjusted for alignment.
Operationlink
Thresholdslink
- Convenience position: 19 degrees
- Auto Front Door open position: 45 degrees
- Full door open position: 70 degrees
- The door can operate on up to a 6 degrees up or grade of 15% vehicle nose up
- Ice breaker retract angle: 6 degrees
- Under normal power operation, the door open velocity: 0.15 - 0.35 m/s
- Under normal power operation, the door close velocity: 0.45 - 0.65 m/s
Openinglink
The front doors can be opened in different ways:
- Opening from outside the vehicle by pressing the exterior door handle for at least 300 ms. This actuates the integrated microswitch.
- Opening from inside the vehicle by pulling the interior door handle. This actuates the integrated microswitch.
- Opening from inside the vehicle by pressing the 'door open' button on the vehicle touchscreen.
The corresponding front door controller receives the signal from any of the above inputs and commands the latch to release. The latch is released then the actuator powers the door to open to the Convenience Position then applies the door actuator brake to hold the door position.
The user may then manually open the door by pulling or pushing the door open as the door controller will detect the pull force and release the door brake to allow the door to be opened manually up to the desired position. Once external force is no longer detected by the door actuator, it will apply the brake again to hold the door position.
If an obstacle is detected (over-current event by actuator) during opening operation, the opening operation is stopped and the door brake is applied.
The door will only open when the vehicle is stationary.
Closinglink
The front doors can be closed in different ways:
- Closing from outside the vehicle by pressing the exterior door handle for at least 300 ms.
- Closing from inside the vehicle by pulling the interior door handle.
- Closing from inside the vehicle by pressing the brake (only for the driver side door).
- Closing from inside the vehicle by pressing the 'door close' button on the vehicle touch screen.
- Closing from either inside or outside the vehicle by manually pushing or pulling the door closed. The door actuator will detect the external push/pull force and release the door brake to allow the door to be closed manually.
- Closing from either inside or outside the vehicle by pressing the top button of the key fob.
The corresponding front door controller receives the signal from any of the above inputs and commands the door motor to close the door.
If the pinch sensor is actuated during the door closing operation, the door closing operation is stopped.
Auto front door (user option)link
The 'Auto Front Door' feature automatically opens the driver door when approaching the vehicle as if a chauffeur or taxi driver would do. The 'Auto Front Door' feature only works when carrying a valid key fob. The feature can be enabled and disabled by the user via the vehicle touch screen.
Depending on the direction the vehicle is approached, the door will open in 1 or 2 stages. - When approaching the vehicle from the rear of the vehicle, the driver front door will automatically open to the fully open position. - When approaching the vehicle from the front of the vehicle, the driver front door will first open to the convenience position. This allows for enough space to pass the door. When the user walks past the front door and stands in front of the rear door and no obstacles are detected, the door will open to the fully open position.
The fully open position may vary depending on obstacles detected near the front door. The location of the user is determined by the detected key location and the rear door ultrasonic sensor.
Power cinching latchlink
The power cinching function is intended to enable the automatic completion of the door closure from secondary to primary latch. The cinch operation is controlled from within the latch. To initiate cinching, bring the door to engage the secondary latch.
The latch mechanism can always function in a conventional manner in that the power cinch can be bypassed and operating the manual release as usual. Slamming the door to primary latch always bypasses the cinch operation.
The cinching operation can be interrupted at any point in time. Pulling the interior release handle during the power cinch operation will release the door and interrupt the cinch operation. Independently from the electrical interruption, the manual release proceeds to release the door in the conventional manner, thus, providing a redundancy, which is available at all times and conditions.
Door operation in different conditionslink
Windy environments: The door actuator limits speed of motion in the opening direction if moved too quickly by external force. This limit is meant to prevent the wind from swinging the door open too fast. This limit does not apply in the closing direction in order to allow the door to be slammed by the user.
On grade: The front door controller has an integrated accelerometer that is used to detect the vehicle grade (incline, decline, tilt). Based on the grade of incline, decline, and tilt, the door actuator power and brake will be applied or released as necessary for smooth operation of the door.
The torque of the hinge axis of the door varies depending on the opening angle of the door as well as the tilt and incline/decline grade. For example, Figure 1 shows the torque on the hinge axis of the front door as the door opens to its full open position. It clearly shows how the motor delivers a higher torque when the door angle is small and that the torque decreases as the door opens. This is due to the geometry of the linkage between motor and door. Figure 2 shows the same torque but on a 10% grade nose upwards. Note that the scale of the y-axis is much larger. The further the door opens the more torque the motor needs to deliver. Obviously this is because gravity has a larger effect on the door as it opens. Similarly, the torque curves vary for all ranges of vehicle orientation.
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Obstacle detectionlink
The door can detect obstacles in different ways.
- Actuator overcurrent: The front door controller can detect an obstacle in the way of closing or opening operation by monitoring the door actuator current for an overcurrent event, indicating an external force against the opening or closing operation. The door closing or opening operation will stop before it reaches the force threshold level of exertion on the obstacle. If the door detects an object via the actuator overcurrent event during the close operation, the door actuator will stop and apply the brake. (Reverse approximately 5°)
- Door Controller Accelerometers: The front door controller has an integrated accelerometer that is used to detect an external force on the door during closing or opening operation for obstacle detection.
- Pinch Sensors: There is a pinch strip sensor along the rear edge of the door that is used to detect an object in the way of the door and vehicle body at the B-pillar when the door is closing. The door will stop closing operation and apply the door actuator brake when a pinch is detected. If the pinch strips are pinched when the door is requested to be closed, the door will not close automatically.
Note
With the introduction of the 2nd generation door latches, the pinch strip sensors are not longer installed.
Door unzeroedlink
The power front door has lost its calibration. This means that the door module does not know the position of the door. This can happen when the door controller goes to sleep while a front door was open, when the door module was reset while the front door was open, or while the measured door opening angle is outside expected range. When the front door is 'unzeroed' the powered operation and automatic operation are disabled but the door motor will continue to release or apply its brake to allow manual operation. The front door can simply be re-calibrated by closing the door manually.
Ice breakerlink
The ice breaker is a plunger inside the front door that extends to apply additional opening force against the B-pillar body for the door in the case of ice freezing the door shut. The ice breaker actuator is activated when the door is determined to be blocked upon latch release. The door is considered blocked when the door is commanded to open but the door latch does not report to be in the unlatched position within a certain amount of time. The door latch will be commanded to release at another time. If the door latch still does not report to be in the unlatched position within the same amount of time, the ice breaker extends as it is likely that the door is iced shut.
The ice breaker retracts when the front door angle exceeds to 'ice breaker retract angle', or when the encoder is sensing that the door is moving towards the closing position. In the case that the door is unzeroed, the door module doesn't know the open angle of the door and therefore cannot determine the previous conditions. In that case the ice breaker retracts when the door is commanded to close via the interior door handle, exterior door handle, touch screen, or brake press.
Brake calibrationlink
The front door actuator uses brake force calibration parameters that are particular to each individual door actuator. These parameters are determined based on a calibration test performed during manufacturing of the actuator and are provided by the manufacturer. The brake calibration parameters consist of two values (the slope a and y-intercept b of a linear equation y=a*x+*b) that define the linear relation between the drive voltage of the electromechanical brake and the brake force in each direction (clockwise & counter-clockwise).
When installing a new door actuator, the initial actuator calibration parameters need to be programed to the corresponding front door controller. This can be done by running the calibration procedure in Toolbox. Each actuator will have different calibration parameters due to manufacturing tolerance stack-ups of the different parts of the actuator so it is necessary to use the calibration parameters provided by the manufacturer in order to have smooth operation of the actuator brake when installed. If no calibration parameters are programed with a new actuator, the door controller will use default parameters, but this may result in rough or abnormal door operation. (Refer to the service manual for the latest information on the calibration procedure).
Brake wear compensationlink
The front door controller will compensate for brake wear over many brake slip cycles by using a characterized shift in brake force over the life of the door actuator.
Low 12V powerlink
The front door interior latch release is mechanically linked to the latch, so the door latch can be released from inside the vehicle during loss of 12V power. The exterior door handle release will not operate during loss of 12V power.
The door actuator brake is a normally closed brake which requires 12V power to be released. When there is no 12V power the brake will remain closed, but the door can still be opened by applying enough force to overcome the brake friction by manually opening the door.
Crash Responselink
The interior and exterior releases are both disabled during a crash event.
- For the exterior release, latch release is disabled within 50 milliseconds of a “crash active” event and remains disabled until 10.5 seconds after the “crash active” event.
- For the interior release, key fob release request, and MCU release request, movement of the door and latch release request is disabled 300 milliseconds after a “crash active” event and remains disabled for 450 milliseconds after the “crash active” event.
All doors and rear trunk will unlock within 100 ms of a “crash active” event and all lock requests are ignored for 10 seconds after the “crash active” event.