Parking Aid - System Operation and Component Description

System Operation

Parking Aid - Audible

System Diagram

Network Message Chart

  BCM Network Input Messages

  IPC Network Input Messages

Audible Parking Aid Operation

The parking aid system is active only when the transmission selector is in reverse. For vehicles equipped with an automatic transmission, the BCM uses the transmission gear lever position message sent from the TCM to determine the selector lever position. For vehicles equipped with a manual transmission, when the gearshift lever is in reverse, the BCM receives voltage from the reverse lamp switch on a hardwired circuit. Automatic transmission vehicles utilize a brief time delay in between the driver placing the selector lever in reverse and activation of the parking aid system to prevent unintended parking aid system activation when the driver is moving the selector lever from park to drive.

The BCM calculates the distance to an object within a 170 degree semicircular area (azimuth) around the rear of the vehicle using the 4 ultrasonic parking aid sensors located in the rear bumper cover. The BCM supplies voltage and ground to the 4 rear parking aid sensors via common circuits while monitoring a signal return circuit from each sensor any time the ignition is on. The system is capable of detecting objects at a distance of approximately 1800 mm (71 in) from the rear of the vehicle and 300 mm (12 in) above the ground.

Only objects that reflect a sufficient amount of sound waves can be detected by the rear parking aid system. The surface properties, size and composition of an object can affect the ability of the parking aid system to detect the object. Incorrect sensor alignment or installation, dirt or ice covered sensors, heavy rain and snow can also cause objects not to be detected.

Parking Aid Audio Chime

When the parking aid system is active and an object has been detected by one of the rear parking aid sensors, the BCM sends the parking aid chime request message to the IPC to generate an audio tone. The IPC performs an arbitration function to prioritize the incoming chime request and then directs the ACM to reduce the current audio volume and sound the parking aid chime through the rear speakers.

When the selector lever is in reverse and an object is detected by the rear parking aid system, a variable rate warning tone is sounded through the audio system speakers. As the object approaches the rear of the vehicle, the warning tone rate increases in frequency. When the object is within 300 mm (12 in) of the rear of the vehicle, the warning tone becomes continuous. If a stationary or receding object is detected more than 12 in (300 mm) from the side of the vehicle, the audible warning sounds for only 3 seconds. If the system detects an object approaching again, the audible warning is sounded.

Component Description

Parking Aid Sensors

The parking aid sensors are wide beam ultrasonic sensors. The sensors continuously send out ultrasonic signals to detect objects and communicate the information back to the BCM .

BCM

The BCM calculates and reports (via audio system tones) the distance between the rear of the vehicle and an object when the transmission is in reverse. For additional information about BCM operation,
Refer to: Module Controlled Functions - System Operation and Component Description (419-10 Multifunction Electronic Modules, Description and Operation).

Copyright © Ford Motor Company