Normal Operation
WARNING: This page is about a different car, the 2005 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.
The parking aid system is enabled when the ignition switch is in the RUN position and REVERSE gear is selected. The parking aid module calculates the distance to an object by the use of 4 ultrasonic sensors mounted in the rear bumper. The parking aid sensors can detect obstructions in the path behind the vehicle. A 750 Hz variable warning tone is generated from a parking aid speaker. The parking aid speaker increases the warning tone rate as the vehicle gets closer to an obstacle.
If no objects are present, the parking aid PIDs should read 255 cm (100 in).