Operation
OPERATION
The park assist display provides the vehicle operator with visual feedback by illuminating amber or red Light Emitting Diode (LED) units individually or in unison, and audible feedback by energizing an audible tone transducer on the display electronic circuit board to emit either an intermittent or a continuous tone. While the park assist system is active, the number, position and color of the illuminated LED units as well as the audible signal frequency indicate the relative position and distance of obstacles detected at the rear of the vehicle.
The park assist display receives battery current and ground from and is completely controlled by the park assist module. The display also contains an electronic communication chip that allows bi-directional communication to occur with the park assist module over a dedicated serial bus line. The microprocessor in the park assist module completely controls the display outputs, continually monitors the display status, and will store a Diagnostic Trouble Code (DTC) in memory for any monitored fault it detects in the park assist display. The illumination intensity of the LED units is also controlled by the park assist module based upon internal programming and electronic panel lamps dimming messages received over the Controller Area Network (CAN) data bus.
When the ignition switch is turned to the ON position, all 16 of the LED units in the display will illuminate in unison for approximately 1 second as a bulb test. This output will be interrupted if the system is active and senses an obstacle. Following the conclusion of the bulb test, when the system is active but no obstacle is detected, the display will indicate system readiness by illuminating the two outermost amber LED units (1) at a reduced intensity. As an obstacle is detected, the outermost amber LED unit (5) on the side of the vehicle where the obstacle was detected will be illuminated at normal intensity and a single short audible tone (one-half second duration) is sounded. Then additional amber LED units (6) will begin illuminating inward (2 or 4) as the obstacle gets closer until, finally, the two red LED units (7) are illuminated.
When the final red LED unit (3) is illuminated, the obstacle is approximately 40 centimeters (16 inches) from the rear corner of the vehicle or approximately 50 centimeters (19.7 inches) from the rear bumper face and an intermittent audible tone will be generated. The frequency of the audible tone will increase as the obstacle continues to become closer until the tone is continuous when the obstacle is about 15 centimeters (6 inches) from the rear corner of the vehicle or about 30 centimeters (11.8 inches) from the rear bumper face. Whenever a park assist audible tone is being generated, the park assist module sends electronic messages to the radio over the CAN data bus to mute the audio system. The audible tone will be cancelled after about two seconds if the detected distance to the obstacle remains constant. See the Park Assist Display Outputs table for additional details.
The hard wired circuits between components related to the park assist display may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information in Diagrams/Electrical. 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 display 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 display or the electronic controls and communication related to park assist display operation requires the use of a diagnostic scan tool.
