Principles of Operation

WARNING: This page is about a different car, the 2008 Mercury Mariner and 2008 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

The parking aid system detects objects behind the vehicle when the REVERSE (R) gear is selected. The parking aid module (PAM) calculates the distance to an object by the use of 4 ultrasonic sensors mounted in the rear bumper. The PAM does this by calculating the distance to an object within the 170 degree semicircular azimuth area around the rear of the vehicle.

The parking aid sensors detect objects approximately 1.8 m (5.9 ft) from the rear of the vehicle, 50 cm (1.6 ft) from the rear side of the vehicle, and 16 cm (6 in) above the ground. A 750 Hz variable warning tone is generated from a parking aid speaker attached to the PAM. The parking aid speaker increases its warning tone rate as the vehicle gets closer to an obstacle. When an object is detected within 25 cm (10 in) of the sensors, the warning tone becomes continuous.

The PAM will prove out the indicator, located in the parking aid disable switch, by illuminating the indicator for 3 seconds. If the PAM detects a failure, it illuminates the indicator for as long as the failure condition exists and the ignition switch is in the RUN position. The PAM is on the International Standards Organization (ISO) 9141 network and can be diagnosed with a scan tool.