Park Assist System Chime/Buzzer - Operation

PARK ASSIST SYSTEM

The park assist system is active only when the status of the ignition switch is ON, the parking brake is released, the transmission gear selector is in the REVERSE position and the vehicle speed is less than about 16 kilometers per hour (10 miles per hour). In vehicles equipped with this system, the system is enabled from the factory as a default. However, the system can be manually disabled or enabled by the vehicle operator using either the park assist OFF switch integral to the instrument panel switch pod (also known as the Accessory Switch Bank Module/ASBM), or by using the Personal Settings menu of the Electronic Vehicle Information Center (EVIC) and the push buttons of the EVIC switch pod in the left horizontal spoke of the steering wheel.

If the vehicle operator does not want the system active, the park assist OFF switch will disable the system for the remainder of the current ignition cycle or until the park assist OFF switch is actuated a second time, whichever occurs first. Optionally, certain features of the system or the entire system can be disabled until enabled again using the Personal Settings menu choices of the EVIC.

Reasons for disabling the system include trailer towing, off road use and driving when the tailgate is in the down position. With a trailer attached or the tailgate down the audible and visual park assist alerts would be incessant whenever the gear selector was in the REVERSE position due to the proximity of the trailer or the tailgate to the rear bumper of the vehicle. Similarly, operating the vehicle off road may cause the park assist alerts to become distracting due to the proximity of large trees or boulders and the extreme rear approach angles that may be encountered while maneuvering through off road trails or terrain.

While the system is disabled, a PARK ASSIST SYSTEM OFF textual message will appear in the EVIC display whenever all of the other conditions (ignition, parking brake, gear selector and vehicle speed) would dictate park assist operation if the system were enabled. When the system is enabled, a PARK ASSIST SYSTEM ON graphic and textual message will appear in the EVIC display of the IC, and a PARK ASSIST READY graphic and textual message will appear in the display whenever the gear selector is in the REVERSE position.

The microcontroller-based Park Assist Module (PAM) (also known as the ParkTronic System/PTS module) is the central component of the park assist system. It supplies voltage to the park assist sensors, receives and analyzes data from the sensors, calculates and communicates the proper display information to the EVIC, 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 PAM operates on battery voltage received through a fuse in the Power Distribution Center (PDC) and is grounded through a take out and eyelet terminal of the body wire harness that is secured to the body sheet metal.

Four ultrasonic park assist sensors in the rear bumper 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 PAM, then signal the PAM when an echo of the reflected sound pulses is received. The detection distance range from the rear of the vehicle is about 0.3 meters (11.8 inches) to about 2.0 meters (80 inches), and the detection height range from the ground is about 0.2 meters (7.8 inches) to about 0.8 meters (31 inches). The detection area extends somewhat around both rear sides (corners) of the vehicle.

The EVIC display unit provides the vehicle operator with a graphical representation of the vehicle along with numerous arc sections that illustrate the relative location and range of detected obstacles. The display is visible directly in front of the vehicle operator and operates based upon the electronic message inputs received from the PAM over the CAN data bus. There are two regions at the rear of the vehicle designated for arc alerts: Left and Right. Each region consists of four zones. The zones range from furthest to nearest from the rear of the vehicle. All four arc sections are illuminated until the furthest zone is reached, at which point the arc sections begin to extinguish then change from solid to flashing as the obstacle becomes closer.

Meanwhile, the radio generates audible indications of a detected object by emitting a series of chime tones that grow progressively higher in frequency as the vehicle gets closer to the object. As the vehicle comes within about 35 centimeters (14 inches) of the object, the audible warning changes from a high frequency series of chime tones to a single continuous tone. If the audio system is active when the radio receives a chime request message from the PAM, the audio output will be muted automatically while the park assist audible warnings are being generated.

When the PAM 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 and, sends an electronic message to the EVIC and the EVIC displays a SERVICE PARK ASSIST SYSTEM textual message. When the system is disabled by the PAM, a PARK ASSIST SYSTEM DISABLED textual message will appear in the EVIC display of the IC whenever the gear selector is in the REVERSE position.

The hard wired circuits between components related to the park assist system may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin out information and location views for the various wire harness connectors, splices and grounds.

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 or the electronic controls and communication related to park assist system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.