Parking Aid - System Operation and Component Description: Notes
System Operation
Active Park Assist
System Diagram
Network Message Chart
PAM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| ABS active | ABS module | Disables the active park assist if an ABS activation occurs. |
| Active park assist steering angle control status | PSCM | Provides the steering angle status confirmation to the PAM. |
| Active park assist mode request | APIM | Allows the driver to change the parking aid settings through the centerstack infotainment display. |
| EPAS failure | PSCM | Disables the active park assist if an EPAS failure occurs. |
| Gear lever position | TCM | Used to determine the current gear selection. |
| Stability-traction control event in progress | ABS module | Disables the active park assist if a stability or traction control system activation occurs. |
| Stability-traction control indicator request | ABS module | Disables the active park assist if a stability or traction control system fault occurs. |
| Steering wheel angle | ABS module | Used to determine the current steering angle. |
| Trailer lamp connected | TRM | Deactivates the system if a trailer is connected. |
| Turn signal switch status | SCCM | Determines which side of the vehicle the intended parking space is located on. |
| Vehicle speed | PCM | Disables the active park assist system if the vehicle speed exceeds a preset threshold when the system is active. |
| Vehicle yaw rate | ABS module | Used to determine the current vehicle yaw rate. |
| Wheel speed data | ABS module | Used to confirm vehicle movement and calculate distance traveled during active park assist maneuvers. |
| Wheel rotation data | ABS module | Used to confirm wheel rotation during active park assist maneuvers. |
| Wheel rotation direction | ABS module | Used to confirm wheel rotation direction during active park assist maneuvers. |
PSCM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Active park assist steering angle request | PAM | Used to command the steering angle during active park assist maneuvers. |
| Steering wheel angle | ABS module | Used to determine the current steering angle. |
| Vehicle speed | PCM | Disables the active park assist if vehicle speed is too high during a maneuver. |
IPC Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Active park assist chime request | PAM | Used to command audio prompts during active park assist maneuvers. |
| Parking aid fault status | PAM | Used by the IPC to display the active park assist fault messages to the driver. |
APIM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Active park assist mode available | PAM | Allows the driver to see what parking aid settings are available through the centerstack infotainment display. |
| Parking aid fault status | PAM | Used by the centerstack infotainment display to display the active park assist fault messages to the driver. |
Active Park Assist
The PAM communicates with several modules to control the functions of the active park assist system. The PAM utilizes steering angle, vehicle wheel rotation count and direction, active park assist sensor inputs, parking aid sensor inputs, vehicle speed and transmission gear selection to calculate vehicle position and distance in relation to the parking space. The inputs are used by the PAM to command the steering angles required to maneuver the vehicle into or out of a parallel parking space or into a perpendicular parking space.
Pressing and releasing the active park assist switch activates the system. The active park assist switch is a hard wired input to the PAM.
Pressing and releasing the active park assist switch at any time during an active park assist maneuver disables the active park assist system. If the system is disabled by the operator after the system starts to control the steering, the centerstack infotainment display displays an active park assist canceled message followed by a warning chime.
The PAM continuously monitors the active park assist sensor signals any time the ignition is on. When no signal is detected from an active park assist sensor, the PAM sets a DTC.
If an input module fault or other system malfunction is present, the active park assist system is disabled. An active park assist fault message is shown on the centerstack infotainment display and/or on the IPC message center display and a DTC is set in the PAM. In addition to possible vehicle faults, certain driver actions and vehicle operating conditions can cause the active park assist system to be temporarily disabled.
Certain conditions can cause the active park assist system to incorrectly align the vehicle in the parking space:
- A spare tire installed or one of the tires on the vehicle has significantly more or less treadwear than the other tires (one tire being a different size).
- The vehicle has been equipped with various accessories (cycle rack, trailer) which are not recognized by the active park assist system.
- The factory-installed tire size is not used on the vehicle.
- Poor ambient weather conditions such as heavy rain or snow.
- The active park assist sensors are damaged or obstructed.
- The curb along the parking space is irregular.
- The vehicle or objects bordering the space are not positioned correctly.
- The parking space dimensions or parked objects position have changed after the vehicle has initially passed the parking space.
- The ambient temperature changes quickly such as when the vehicle is driven from a heated garage into the cold or just leaving a car wash before the system was activated.
- One of the surrounding parked vehicles has a high or overhanging attachment, such as a salt spreader or a large truck bed, that the sensors cannot detect.
Parallel Parking Operation
After the active park assist system is activated and the PAM has determined the driver is attempting to maneuver the vehicle into a parallel parking space (the active park assist switch is pressed once), the PAM begins searching for a parking space using the front active park assist sensors. The multifunction switch turn signal input from the SCCM determines the side of the vehicle that the PAM searches for a parking space. When a side is selected with the turn signal, the PAM searches on that side of the vehicle until the active park assist is switched off, the ignition is cycled, or the opposite side is selected by the driver. By default, the PAM searches for spots on the passenger side of the vehicle.
The system measures the available parking spaces and its surroundings as the operator drives by to determine if the vehicle can be maneuvered into the available parking space. The PAM uses inputs from the front active park assist sensors, the wheel speed, and wheel rotation data messages to find an acceptable parking space. After a space has been located, a chime is sounded through the audio system and the centerstack infotainment display shows a message informing the driver that a parking space has been located on the left or right side and requesting the driver to pull forward to park. After the driver moves the vehicle forward to the appropriate start position, as determined by the PAM, the system requests the driver to stop, shift the transmission into reverse and remove hands from the steering wheel. After the transmission is in reverse and no driver input torque on the steering wheel is detected (driver has removed their hands from the wheel), the active park assist system takes control of the steering and prompts the driver to begin backing into the parking space. The active park assist system sounds tones through the audio system and issues commands through the centerstack infotainment display instructing the driver to back up and pull forward as necessary while the system controls the steering to position the vehicle within the detected parking space. The operator maintains full control of the gear shifting, accelerator and brakes during active park assist maneuvers.
The PAM determines that the parallel parking maneuvers are completed based on the final vehicle alignment. The vehicle should be located approximately 0 to 30 cm (12 in) from the street curb if a curb is detected, otherwise the system aligns the vehicle to the slot end object. When the active park assist maneuver is complete, the centerstack infotainment display displays an active park assist finished message followed by an audible chime.
Parallel Park Out Assist Operation
Parking out assist is available immediately after a parallel park was completed, or after an ignition on. The driver must activate the park assist system by pressing the active park assist switch once then select a side to exit the parking spot using the turn signal before the system measures the location to parallel park out of. Once the turn signal status is received from the SCCM, the PAM verifies the indicated side is clear by analyzing the clearance around the vehicle using input from the active park assist sensors and the parking aid sensors. When the indicated side is clear of obstructions, the centerstack infotainment display shows a message informing the driver to remove hands from the steering wheel and shift to drive (D or S) or reverse gear, depending on the detected clearances to the front and rear of the vehicle. After the transmission is shifted and no driver input torque on the steering wheel is detected (driver has removed their hands from the wheel), the driver is prompted on the centerstack infotainment display to backup slowly in the parking spot. While backing up, the PAM sends the active park assist steering angle request to the PSCM to turn the wheels to an angle which steers the vehicle out of the parallel parking space on the desired side. When the desired steering angle is achieved, the active park assist system sounds tones through the audio system and issues commands through the centerstack infotainment display instructing the driver to pull forward and safely exit the parking spot. The driver may be prompted to shift back and forth multiple times depending on parking spot size for the system to successfully guide the vehicle out of the spot. When the driver is prompted to shift and change directions, the distance between the vehicle and a front or rear object is 35 cm (14 in) in North America and South America and 30 cm (12 in) in Asia Pacific.
The PAM determines that the parallel park out assist maneuvers are complete when a clear path to exit the parking space is detected. When the maneuver is complete, the centerstack infotainment display shows a message informing the driver to take control of the steering.
Perpendicular Parking Operation
After the active park assist system is activated and the PAM has determined the driver is attempting to maneuver the vehicle into a perpendicular parking space (the active park assist switch is pressed twice), the PAM begins searching for a parking space using the front active park assist sensors. The multifunction switch turn signal input from the SCCM determines the side of the vehicle that the PAM searches for a parking space. If the turn signal is not active, the PAM defaults to searching on the passenger side of the vehicle.
The system measures the available parking spaces and its surroundings as the operator drives by to determine if the vehicle can be maneuvered into the available parking space. The PAM uses inputs from the front active park assist sensors, the wheel speed, and wheel rotation data messages to find an acceptable parking space. After a space has been located, a chime is sounded through the audio system and the centerstack infotainment display shows a message informing the driver that a parking space has been located on the left or right side and requesting the driver to pull forward to park. After the driver moves the vehicle forward to the appropriate start position, as determined by the PAM, the system requests the driver to stop, shift the transmission into reverse and remove hands from the steering wheel. After the transmission is in reverse and no driver input torque on the steering wheel is detected (driver has removed their hands from the wheel), the active park assist system takes control of the steering and prompts the driver to begin backing into the parking space. The active park assist system sounds tones through the audio system and issues commands through the centerstack infotainment display instructing the driver to back up and pull forward as necessary while the system controls the steering to position the vehicle within the detected parking space. The rear side sensors are used to re-measure the parking spot when the vehicle is backing into the perpendicular spot to improve the measurement accuracy. The operator maintains full control of the gear shifting, accelerator and brakes during active park assist maneuvers.
The PAM determines that the perpendicular parking maneuvers are completed based on the final vehicle alignment. The perpendicular parking aid system attempt to center the vehicle between the two vehicles and align the end vehicle angle with the angle of the parked vehicles. If only one vehicle is detected, the system aligns with that vehicle at a distance of 70 to 80 cm (28 to 35 in) in North America and South America or 55 to 75 cm (22 to 30 in) in Asia Pacific. When the active park assist maneuver is complete, the centerstack infotainment display displays an active park assist finished message followed by an audible chime.
Parking Aid System
The active park assist system uses input from the audible parking aid system when parking the vehicle. Input from the front and rear parking aid sensors help the PAM to determine the position of the vehicle in the parking space. For more information on the operation of the operation of the audible parking aid system, Refer to: Parking Aid - System Operation and Component Description .
EPAS Control
The PSCM controls the steering during active park assist maneuvers based on the active park assist steering angle request message received from the PAM. The PSCM also provides steering column torque data to the PAM to determine if the driver has placed their hand(s) on the steering wheel while the active park assist system has control of the steering.
Active Park Assist Chimes
The active park assist system chimes are controlled by the IPC. Based on the parking aid chime request message received from the PAM, the IPC prioritizes the incoming chime request and then commands the ACM (for vehicles without Bang and Olufsen audio system) or the DSP (for vehicles with Bang and Olufsen audio system) to sound the chime through the audio system speakers. In the event of an audio system fault, the IPC sounds the chimes through an integral speaker. For more information on the IPC warning chimes, Refer to: Warning Chimes - System Operation and Component Description .
Active Park Assist Message Display
Active park assist messages are shown on the centerstack infotainment display. Conditions that can cause the active park assist system to be temporarily unavailable or cause the current active park assist system maneuver to be cancelled are:
| Cancellation Event | FDIM Message/Audio Chime |
|---|---|
| Vehicle speed above 18 mph (29 km/h) during the measuring/searching phase for 30 consecutive seconds. Note, the screen is shown while driving faster than 18 mph (29 km/h), screen goes away and system deactivates after 30 seconds. | PARALLEL PARK REDUCE SPEED TO SCAN FOR PARKING SPOT |
| Deactivation of the AdvanceTrac® system by the driver while the active park assist system is currently scanning for parking slots. | ACTIVE PARK ASSIST NOT AVAILABLE REFER TO OWNER GUIDE followed by a chime |
| A vehicle attachment is detected by the reverse parking aid system, such as a trailer or bike rack. The attachments need to be electrically connected to the vehicle to prevent the active park assist from activating. | ACTIVE PARK ASSIST NOT AVAILABLE REFER TO OWNER GUIDE followed by a chime |
| Driver grabbing steering wheel while the active park assist system has control of the steering. | ACTIVE PARK ASSIST CANCELLED BY DRIVER followed by a chime |
| The driver changes from reverse to drive before the vehicle is far enough inside the parking space. | |
| Vehicle speed above 6 mph (10 km/h) when the active park assist system has control of the steering. | ACTIVE PARK ASSIST DEACTIVATED followed by a chime |
| Deactivation of the AdvanceTrac® system by the driver while the active park assist system has control of the steering. | |
| An ABS activation or an AdvanceTrac® system activation occurs while the active park assist system has control of the steering. | |
| Maximum number of moves is exceeded during any parking maneuver. The move number is incremented each time the driver shifts gears, 9 is the maximum. |