Parking Aid - System Operation and Component Description
System Operation
Active Park Assist
System Diagram
Network Message Chart
Parking Aid Module (PAM) Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| ABS active | ABS module | Used to disable the active park assist if the ABS is activated. |
| Ambient air temperature | PCM | Used to temperature compensate the parking aid sensor inputs. |
| Door ajar status | BCM | Used to disable the active park assist if any door except the driver's door is opened. |
| EPAS failure | PSCM | Used to disable the active park assist in the event of an EPAS system failure. |
| Power mode | BCM | Used to communicate the ignition switch position. |
| Selector lever (PRNDL) position | PCM | Used to communicate the selector lever position. |
| Stability control brake active | ABS module | Used to disable the active park assist if the stability control system is activated. |
| Steering angle status | SASM | Used to confirm steering angle requests. |
| Torsion bar torque | PSCM | Used to disable the active park assist if the driver intervenes by applying rotational torque to the steering wheel during an active park assist event. |
| Traction control brake active | ABS module | Used to disable the active park assist if the traction control system is activated. |
| Turn signal switch status | SASM | Used to establish which side of the vehicle the intended parking space is on. |
| Wheel data | ABS module | Used to confirm vehicle movement and calculate distance traveled. Contains wheel size, rotation count and direction data. |
APIM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Active park assist status | Parking Aid Module (PAM) | Used to display parking aid system status and driver input request messages on the FDIM. |
ACM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Active park assist status | Parking Aid Module (PAM) | Used to sound a chime through the audio system as driver input request messages are displayed on the FDIM. |
PSCM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Steering angle request | Parking Aid Module (PAM) | Used to command the steering angles calculated by the Parking Aid Module (PAM) during an active park assist event. |
Active Park Assist Operation
The Parking Aid Module (PAM) communicates with several modules to control the functions of the active park assist system. The active park assist system utilizes steering angle inputs, vehicle wheel roll count, wheel direction, active park assist sensor inputs, vehicle speed and transmission selection to calculate vehicle position and distance in relation to the parking space. The Parking Aid Module (PAM) uses these inputs to command the steering system to assist with the steering wheel control to maneuver the vehicle into the parking space.
When the active park assist switch is pressed, the centerstack infotainment display displays the message "Searching for parking space on left/right side.". The multifunction switch turn signal input determines the side of vehicle in which the driver is searching for a parking space. If the turn signal is not selected, the active park assist system 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 minimum parking space length the active park assist system identifies is approximately 1.2 times the length of the vehicle and is determined by inputs from the active park assist sensors and the wheel rotation data.
Once a parking space is located, the centerstack infotainment display displays "Parking space found on left/right side. Pull forward to park." followed by an audible chime sounded through the audio speakers by the ACM. The operator pulls the vehicle forward and the centerstack infotainment display displays the message "Parking space found on left/right side. Stop vehicle to park.". Once the operator has stopped the vehicle, the centerstack infotainment display displays the message "Remove hands from steering wheel. Shift to (R) to park on left/right side." then the message "Parking on left/right side. Back up slowly.". The active park assist system takes control of the steering when the transmission is placed in REVERSE (R) and no steering wheel operator input torque is detected by the PSCM. The operator has full control of shifting gears, the accelerator and the brake pedal.
When the vehicle has backed close to the vehicle behind, the message, "Pull forward slowly." is displayed and the active park assist system continues to control the steering as the operator moves the vehicle forward. The active park assist system may offer subsequent backward and forward maneuvers (and similar messages) before finalizing the parking sequence.
The Parking Aid Module (PAM) determines the active park maneuvers are completed based on the final vehicle alignment. The vehicle should be located approximately 0 to 304.8 mm (12 in) from the street curb if a curb is detected, otherwise the system aligns the vehicle to the front vehicle. The centerstack infotainment display displays the message "Active Park Assist Finished" followed by an audible chime sounded through the audio speakers by the ACM.
Certain conditions can cause the active park assist system to incorrectly align the vehicle in the selected parking space:
- A spare tire or one of the vehicle tires has significantly more or less tread wear than the other tires.
- 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 sizes are not used on the vehicle.
- Poor weather conditions such as heavy rain or snow exist.
- 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 system aligns the vehicle to the front vehicle and the driving angle when the curb is not detected.
- The parking space length or parked objects position have changed after the vehicle has initially passed the parking space.
- The temperature around the vehicle changes quickly such as the vehicle driven from a heated garage into the cold or just leaving a car wash before the system was used.
- One of the parked vehicles has a high attachment, such as a salt spreader or moving truck bed, the sensors cannot detect.
Pressing and releasing the active park assist switch at anytime 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 the message "Active Park Assist Cancelled" or "Active Park Assist Deactivated" followed by a warning chime.
Electronic Power Assist Steering (EPAS) Control
The EPAS gear assembly controls the steering portion of the active park assist system based on messaged inputs from the Parking Aid Module (PAM).
Active Park Assist Message Display
Active park assist messages are displayed in the centerstack infotainment display. Conditions that cause the active park assist system to be cancelled (and the corresponding display/chime) are:
| Cancellation Event | Message Center Message/Audible Chime |
|---|---|
| Grabbing the steering wheel while the active park assist system is controlling the steering. | "Active Park Assist cancelled by driver input" followed by a chime |
| Vehicle speed above 29 km/h (18 mph) during measuring phase for 30 consecutive seconds. | "Reduce Speed" |
| Vehicle speed above 9.7 km/h (6 mph) when the system is controlling the steering. | "Active Park Assist cancelled by high speed" followed by a chime. |
| Deactivation of the Advance Trac® system by the operator, or an ABS or Advance Trac® event occurs while the active park assist system has control of the steering. | "Active Park Assist cancelled by Advance Trac" or "Active Park Assist cancelled by Anti-lock Brake System event" followed by a chime |
| Any vehicle door (except the driver door) or liftgate is opened when the active park assist system is controlling the steering, the operator engages drive (D) before the vehicle is far enough inside the parking space, or the system cannot follow the desired steering path. | "Active Park Assist cancelled" followed by a chime |
| A vehicle attachment is detected, such as a trailer or bike rack, by the reverse parking aid system. | "Active Park Assist not available" followed by a chime |
| Any door (except the driver door) is ajar. | "Active Park Assist not available" followed by a chime |