Parking Aid - System Operation and Component Description: Notes
System Operation
Parking Aid - Audible
System Diagram
Network Message Chart
PAM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Ignition key type | BCM | Used to disable the parking aid menus when a MyKey® is in use. |
| Ignition status | BCM | Used to communicate the ignition switch state. |
| Outside air temperature | HVAC | Used to temperature compensate the parking aid sensors. |
| Parking aid enable request | IPC | Used to enable or disable the rear parking aid (Vehicles with rear parking aid only). |
| Parking aid switch request | Front Controls Interface Module (FCIM)-B | Used to enable or disable the rear parking aid and front parking aid (vehicles with rear parking aid and front parking aid). |
| Gear lever position | TCM | Used to enable or disable the rear parking aid or front parking aid depending on the gear lever position. |
| Vehicle speed | PCM | Used to disable the parking aid if the vehicle speed exceeds a preset threshold. |
IPC Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Audio system response status | ACM | Used to provide audio chime status feedback to the IPC. |
| DSP Chime request | DSP | Used to provide chime status feedback to the IPC. |
| Parking aid chime request | PAM | Used to command parking aid warning tones through the IPC chime arbitrator. |
Audible Parking Aid System Operation
The rear parking aid system calculates the distance to an object around the rear of the vehicle using 4 ultrasonic sensors. The rear parking aid sensors detect objects approximately 180 cm (70 in) from the rear of the vehicle, 50 cm (20 in) from the rear side of the vehicle, and 30 cm (12 in) above the ground. To detect objects behind the vehicle, the PAM supplies voltage and ground to the rear ultrasonic sensors while monitoring a signal return circuit from each sensor. The 4 rear sensors share common voltage and ground circuits.
The front parking aid system calculates the distance to an object around the front of the vehicle using 4 ultrasonic sensors. The front parking aid sensors detect objects approximately 70 cm (27 in) from the front of the vehicle, 50 cm (20 in) from the front side of the vehicle, 30 cm (12 in) above the ground. To detect objects in front of the vehicle, the PAM supplies voltage and ground to the front ultrasonic sensors while monitoring a signal return circuit from each sensor. The 4 front sensors share common voltage and ground circuits. Vehicles equipped with active park assist must be equipped with front parking aid.
The rear parking aid is not active when the vehicle is in drive.
Only objects that reflect a sufficient amount of sound waves are detected by the parking aid sensors. The surface properties, size and composition of an object can affect the ability of the parking aid system to detect the object.
Parking aid operation may also be affected by:
- Improper sensor installation or alignment
- Dirt or ice covered sensors
- Heavy rain or snow
The parking aid system detects objects under the following conditions:
- The vehicle is in REVERSE (rear parking aid).
- The vehicle is in motion in any gear except NEUTRAL (front parking aid and side sensing system, if equipped).
- The vehicle is moving toward the object.
- The vehicle is stationary and the object is moving toward the vehicle.
- The vehicle and object are both moving toward one another.
The following may trigger false detections when driving at slow/creeping speeds (could be decelerating, or accelerating) less than 12 km/h (8 mph), but not at standstill:
- Near another vehicle equipped with park aid sensors. The other vehicle could be several meters away (it does not have to be within the detection zone of the host vehicle).
- Near a semi truck or school bus with air brakes (while the bus/truck is applying their brake)
- Near some other interfering signal near the ultrasonic sensor frequency
As the distance to the obstacle decreases, the indicator blocks illuminate and move toward the vehicle icon as displayed on the FCDIM or FDIM. If there is no obstacle detected, the distance indicator blocks show greyed out.
Side Sensing
The side sensing system calculates the distance to an object around the sides of the vehicle using the four active parking aid sensors used for the active park assist. The side sensors detect objects approximately 60 cm (24 in) from the side of the vehicle. To detect objects on the sides of the vehicle, the PAM supplies voltage and ground to the front ultrasonic sensors while monitoring a signal return circuit from each sensor. The 2 front side sensors share common voltage and ground circuits with the front parking aid sensors. The 2 rear side sensors share common voltage and ground circuits with the rear parking aid sensors.
Parking Aid Audible Alert
Audio system volume is automatically reduced when a parking aid alert tone is sounded. The alert tone frequency increases as the vehicle gets closer to an obstacle. When an object is detected within 30 cm (12 in) of the sensors, the warning tone becomes continuous. When the vehicle stops moving the continuous tone stops after 3 seconds until the vehicle moves again. Objects detected outside the continuous tone area to the side of the vehicle generate a warning tone for 3 seconds. The warning tones are prioritized to the closest object. If the front and rear objects are located the same distance from the vehicle, the rear object is prioritized.