Park Assist System

PARK ASSIST SYSTEM

The park assist system is active only when the ignition switch is in the ON or START positions, the parking brake is released, the transmission gear selector lever is in either the REVERSE position and the vehicle speed is less than 16 kph (10 mph) or, the DRIVE position and the vehicle speed is less than 14 kph (8 mph) on deceleration, or 18 kph (12 mph) on acceleration. The park assist system is enabled from the factory as a default but can be disabled or enabled using either the manual cut-off switch, integral to the instrument panel switch pod, or by using the personal settings menu of the Electronic Vehicle Information Center (EVIC), if equipped. For more information on EVIC operation .

Reasons for disabling the system include trailer towing, off road use and driving conditions where the tailgate is in the down position. With a trailer attached to the vehicle the audible and visible park assist alerts would be incessant whenever the gear selector lever was in the REVERSE position due to the proximity of the trailer to the rear of the vehicle, as well as operating the vehicle at low speeds with the tailgate in the down position and the gear selector in the DRIVE position. 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 on off road trails or terrain. When the system is disabled, a PARK ASSIST OFF textual message will appear in the Electronic Vehicle Information Center (EVIC) display, if equipped whenever the gear selector lever is in the REVERSE position.

The microprocessor based park assist 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 Cab Compartment Node (CCN), 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 Junction Block (JB), and is grounded through a take out and eyelet terminal of the body wire harness that is secured by a screw to the left inner D-pillar.

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 park assist module, then signal the module 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 park assist display, located within the EVIC unit, provides the vehicle operator with a visual and audible warning if the vehicle comes to within about 40 centimeters (31 inches) of a detected object, when the "Sound and Display" are ON. The display is visible to the vehicle operator only when looking forward and an object is detected within the detection zone. The system will also emit a series of short, intermittent, audible beeps and automatically mute the audio system while the park assist audible warning is being generated. The audible warning changes from intermittent beeps to a continuous tone as the vehicle comes to within 30.5 centimeters (12 inches) of a detected object.

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 and, sends an electronic message to the EVIC. When a message from the park assist module is received by the EVIC for a fault condition, a SERVICE PARK ASSIST SYSTEM textual message is displayed within the EVIC display.

The hardwired 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.