Chime/Buzzer - Operation

PARK ASSIST SYSTEM

The park assist system is active only when the parking brake is disengaged, the ignition switch is in the ON position, the automatic transmission gear selector lever is not in the PARK position, the vehicle speed is less than about 16 kilometers-per-hour (10 miles-per-hour), and the park assist switch is not in the OFF position. When the vehicle is moving forward, only the area ahead of the vehicle is monitored. When the transmission gear selector lever is in the REVERSE position (as well as the NEUTRAL position with an automatic transmission) and a trailer is not connected to the trailer tow connector (if the vehicle is so equipped from the factory), the area to the rear of the vehicle is monitored.

An amber Light Emitting Diode (LED) indicator in the park assist OFF switch button will be illuminated whenever the ignition switch is in the ON position and the system is disabled. Reasons for disabling the system include trailer towing and off-road use. With a trailer attached to the vehicle the audible and visible rear park assist alerts would be incessant whenever the gear selector lever was in the REVERSE (or NEUTRAL with an automatic transmission) position due to the proximity of the trailer to the rear of the vehicle. Similarly, operating the vehicle off-road may cause the front and rear park assist alerts to become distracting due to the proximity of large trees or boulders and the extreme approach angles that may be encountered while maneuvering on off-road trails or in certain off-road terrain.

The microprocessor based park assist module (also known as the ParkTronic System/PTS control unit) is the central component of the park assist system. The module supplies voltage to the park assist sensors (also known as ParkTronic System/PTS sensors), the park assist displays (also known as the ParkTronic System/PTS warning element) and the rear park assist buzzer (also known as the rear ParkTronic System/PTS buzzer). The module also analyzes data from the sensors, calculates and communicates the proper display information to the appropriate displays, controls the operation of the buzzer transducers, performs system diagnostics, and communicates with other electronic modules in the vehicle or with a diagnostic scan tool over the Controller Area Network (CAN) data bus. The module operates on battery voltage received through a fuse in the fuse and relay block (also known as the SRB) below the driver side end of the instrument panel, and is grounded through its connection to the vehicle wire harness.

Ultrasonic park assist sensors in the front and rear bumpers allow the park assist system to locate and identify the proximity of nearby obstacles. These sensors each generate ultrasonic sound pulses when triggered by the park assist module, then signal the module when an echo of the reflected sound pulses is received. The detection distance range from the front corners of the vehicle starts at about 65 (26 inches) centimeters towards the front or about 75 centimeters (30 inches) towards the rear. Directly to the front or rear of the vehicle the detection distance ranges from about 100 centimeters (39 inches) at the front or 180 centimeters (71 inches) at the rear to about 30 centimeters (12 inches).

Each display provides a visual indication of a detected object by illuminating one or more LED indicators, amber first followed by red, moving toward the center of the front display or toward the inboard side of the rear displays as the vehicle gets closer to the object. As the vehicle comes to within about 40 centimeters (16 inches) of the object, 1 red LED is illuminated and the buzzer transducer of the front park assist display or the rear park assist buzzer emits a series of short, intermittent, audible tones. The audible warning changes from intermittent to a continuous tone as the final red indicators are illuminated on either side of the displays and the vehicle comes to within 30 centimeters (12 inches) of a detected object. The front and rear audible warnings are generated at one of two distinct frequencies to help differentiate between the front and rear warnings. If the audio system is turned ON, the audio output will be muted automatically while the park assist audible warning is being generated.

When the park assist module monitors a problem in any of the park assist system circuits or components, it stores a fault code or Diagnostic Trouble Code (DTC) in its memory circuit, sounds a continuous audible tone and turns on the two red LED indicators in the display for the active front or rear system for up to 20 seconds, then deactivates the active system and illuminates the amber LED in the park assist OFF switch. This sequence repeats each time the ignition switch is cycled and the affected system is activated.

The hard wired circuits between components related to the park assist system may be diagnosed using conventional diagnostic tools and procedures. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the park assist system or the electronic controls or communication between modules and other devices that provide some features of the park assist system. The most reliable, efficient, and accurate means to diagnose the park assist system, the CAN data bus, the serial data bus or the electronic communication related to park assist system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.