Active Park Assist: Notes
Component Location
Component Location
| Item | Description | Comments |
|---|---|---|
| 1 | Active park assist switch | - |
| 2 | Active park assist sensor | - |
Overview
The active park assist system is a supplementary parking aid that assists the operator in detecting an available parallel parking space and automatically steering the vehicle into the space while the operator controls the accelerator, gearshift and brakes.
The system visually and/or audibly instructs the operator to park the vehicle through messages in the centerstack infotainment display and warning chimes.
System Operation
System Diagram
Network Message Chart
PAM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| ABS event in progress | ABS module | Disables the active park assist. |
| Auto park cancel request | IPC | Disables the active park assist. |
| EPAS Failure | PSCM | Disables the active park assist. |
| Ignition status | BCM | Used as a redundant input to confirm the ignition switch position. |
| Outside air temperature | BCM | Used to temperature compensate the active park assist sensor inputs. |
| Selector lever (PRNDL) status | PCM | Used for active park assist driver messages and for active park steering commands. |
| Stability control event in progress | ABS module | Disables the active park assist. |
| Active park assist information | PSCM | Contains steering angle and steering wheel torque data. Used by PAM to confirm rotation request and to disable active park assist if driver intervenes by applying rotational torque to steering wheel during active park assist event. |
| Ambient temperature | HVAC module | Used for sensor adjustment distance adjustment based on ambient temperature. |
| Steering wheel switch turn signal | SCCM | Used to establish which side of the vehicle the parking space is located on. |
| Navigation rolling wheel count | ABS module | Used for an accurate wheel speed input. |
| Navigation wheel direction | ABS module | Used to confirm vehicle is moving in correct direction. |
| Stability control disabled lamp status | ABS module | Used to indicate stability control lamp status. |
| Steering wheel angle | SCCM | Used to indicate steering wheel angle from the SCCM for vehicles configured for active park assist. |
| Traction control event in progress | ABS module | Disables the active park assist. |
| Traction control event in progress by the engine | ABS module | Used to indicate when a traction control intervention by the engine is present. |
| Vehicle speed | PCM | Used for vehicle speed input to the PAM. |
| Wheel speed data | ABS module | Used for wheel speed input when finding parking spaces. |
PSCM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Active park assist steering angle status | PAM | Send the status to PSCM of the steering angle request from the PAM. |
| Steering angle request | PAM | PSCM rotates steering to achieve requested angle during active park assist event. |
IPC Network Message Chart
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Active park assist steering message center stack display | PAM | Used for active park assist audible chime for driver instruction indication. |
APIM Network Message Chart
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Active park assist steering message center stack display | PAM | Used for active park assist graphics for driver instructions displayed on the FDIM. |
Active Park Assist System
The PAM communicates with several modules to control the functions of the active park assist system.
When the active park assist switch is pressed, the message "Searching for parking space on left/right side." is displayed in centerstack infotainment display. The multifunction switch turn signal input is used to determine the side of vehicle that 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 their surroundings as the operator drives by to determine if the vehicle can be maneuvered into the available parking space. The minimum parking space length that 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.
Once a suitable parking space is located, the message "Parking space found on left/right side. Pull forward to park." is displayed in the centerstack infotainment display followed by an audible chime from the IPC. The operator pulls the vehicle forward and the message "Parking space found on left/right side. Stop vehicle to park." is displayed in the centerstack infotainment display. Once the operator has stopped the vehicle, the message "Remove hands from steering wheel. Shift to <R> to park on left/right side." is displayed in the centerstack infotainment display. The active park assist system takes control of the steering when the transaxle is placed in REVERSE (R) and no steering wheel operator input torque is detected by the PSCM. The operator has full control of gear-shifting, the accelerator and the brake pedal.
The active park assist system continues to control the steering as the operator moves the vehicle forward. When the front bumper of the vehicle is approximately 304.8 mm (12 in) from the front vehicle, the message "Parking on left/right side. Back up slowly." is displayed in the centerstack infotainment display followed by an audible chime from the IPC. The active park assist system may offer subsequent backward and forward maneuvers (and similar messages) before finalizing the parking sequence.
The PAM determines that the active park maneuvers are completed based on the final vehicle alignment. The vehicle can 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 message "Active Park Assist Finished" is displayed in the centerstack infotainment display followed by an audible chime from the IPC.
Pressing and releasing the active park assist switch at any time disables the active park assist system. If the system is disabled by the operator after the system starts to control the steering, the message "Active Park Assist Cancelled" or "Active Park Assist Deactivated" is displayed in the centerstack infotainment display followed by a warning chime.
The active park assist system utilizes steering angle inputs, vehicle wheel roll count, wheel direction, wheel speed sensor inputs, vehicle speed and transaxle selection to calculate vehicle position and distance in relation to the parking space. The inputs are used by the PAM to command the steering system to assist with the steering wheel control to maneuver the vehicle into the parking space.
The rear parking aid sensors are used to detect a vehicle or object located behind the vehicle in the parking space. The rear parking aid speaker sounds a continuous tone when the rear bumper of the vehicle is approximately 304.8 mm (12 in) from the vehicle to the rear and the message "Stop vehicle. Pull forward slowly." is displayed in the centerstack infotainment display followed by an audible chime from the IPC.
If an input module fault or other system malfunction is present, the active park assist system is disabled or prevents the system from activating. The message "Active Park Assist Fault" is displayed in the centerstack infotainment display and a DTC is set in the PAM.
These 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 vehicles tires has significantly more or less tread wear than the other tires.
- 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 be positioned correctly. The system aligns the vehicle to the front vehicle when the curb is not detected.
- The parking space length or parked objects position have changed after the vehicle has 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, that the sensors cannot detect.
Electronic Power Assist Steering (EPAS) Control
The EPAS gear assembly is used to control the steering portion of the active park assist system. The gear assembly is comprised of an electrically controlled power rack assembly and a PSCM.
Active Park Assist Message Display
The IPC message center displays the active park assist message.
The following conditions can result in the active park assist system to be cancelled:
Active Park Assist Message Display
| Item | Description |
|---|---|
| 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 |
| Exceeding vehicle speed above 29 kmh (18 mph) during the measuring phase for 30 consecutive seconds. | "Reduce Speed" |
| Exceeding vehicle speed above 9.7 kmh (6 mph) when the system is controlling the steering. | "Active Park Assist cancelled by high speed" followed by a chime |
| Deactivation of the AdvanceTrac ® System by the operator, an ABS or AdvanceTrac ® event has occurred while the system has control of the steering. | "Active Park Assist cancelled by AdvanceTrac" or "Active Park Assist cancelled by Anti-lock Brake System event" followed by a chime |
| If any vehicle door (except the drivers door) or liftgate is opened when the system is controlling the steering, if 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 Deactivated" 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 is not available" followed by a chime |
| Any door (except the driver door) is ajar. | "Active Park Assist is not available" followed by a chime |