Parking Aid - System Operation and Component Description: Notes

WARNING: This page is about a different car, the 2015 Ford Focus. However, it is still accessible from the selected car via links, so may be relevant.

System Operation

Parking Aid

System Diagram

Courtesy of FORD MOTOR COMPANY

Network Message Chart

Parking Aid Module (PAM) Network Input Messages

Broadcast Message	Originating Module	Message Purpose
Power mode	BCM	Used to command ignition position.
Parking aid enable status	IPC	Used to enable or disable the rear parking aid.
Selector lever (PRNDL) status	PCM	Used to enable the parking aid when the transmission selector is in REVERSE.
Vehicle speed	ABS module	Used to disable the parking aid if the vehicle speed exceeds a preset threshold.

Audio Control Module (ACM) Network Input Messages

Broadcast Message	Originating Module	Message Purpose
Tone request	Parking Aid Module (PAM)	Used to command parking aid sounder tones through rear speakers.

Parking Aid System

The Parking Aid Module (PAM) calculates the distance to an object within a 170 degree semicircular area (azimuth) around the rear of the vehicle. A variable-frequency warning tone is generated through the audio speakers in proportion to the distance the object is from the rear bumper.

The parking aid system calculates the distance to an object around the rear of the vehicle using 4 ultrasonic sensors. The parking aid sensors detect objects approximately 183 cm (72in) from the rear of the vehicle, 30 cm (12in) 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.

Only objects that reflect a sufficient amount of sound waves are detected by the parking aid sensors. The surface properties, size and composition an object can affect the ability of the parking aid system to detect the object.

Also affecting the parking aid operation are:

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
The vehicle is moving toward the object at 5 km/h (3 mph) or less
The vehicle is stationary and the object is moving toward the vehicle at 5 km/h (3 mph) or less
The vehicle and object are both moving toward one another and both are travelling at 5 km/h (3 mph) or less

Once vehicle speed reaches 12 km/h (7.5 mph) the parking aid system is disabled until the speed drops below 5 km/h (3 mph).

Parking Aid Audible Alert

The entertainment system volume is reduced when the park aid warning tone sounds. The frequency of the tones from the audio speakers increases as the vehicle moves closer to the object. When the object is within 305 mm (12 in) of the bumper the tone becomes continuous. When the vehicle stops moving the continuous tone stops after 3 seconds. Objects to the rear side will generate continuous tone only for 3 seconds if the object is stationary or receding from the vehicle. The tone starts again if the object moves closer to the vehicle.