Module, Park Assist: Operation
The microcontroller in the Park Assist Module (PAM) contains the logic circuits that control the park assist system. The module uses On-Board Diagnostics (OBD) and can communicate with other electronic modules in the vehicle as well as with the diagnostic scan tool using the Controller Area Network (CAN) data bus. This method of communication is also used for park assist system diagnosis and testing through the 16-way data link connector located on the driver side lower edge of the instrument panel.
The module provides voltage to each of the park assist sensors located behind the front and rear bumper fascias and to the front and rear park assist displays. The module then monitors return inputs from each of the sensors and the displays on dedicated hard wired data communication circuits. The sensor inputs allow the module to determine when an obstacle is in the front or rear path of the vehicle and enables the module to calculate the relative location of the obstacle, and whether the distance to that obstacle is increasing or decreasing.
Pre-programmed decision algorithms and calibrations allow the module microcontroller to determine the appropriate park assist system outputs based upon the inputs received from the park assist sensors and electronic messages received from other modules in the vehicle over the CAN data bus. When the programmed conditions are met the module sends electronic messages to the park assist displays over a dedicated serial bus to obtain the proper park assist system visual and audible outputs. The module also broadcasts electronic messages over the CAN data bus to enable the other electronic features of the park assist system.
The PAM microcontroller continuously monitors all of the park assist system electrical circuits and components to determine the system readiness. If the module detects a monitored system fault, it sets a Diagnostic Trouble Code (DTC) and sends the appropriate electronic messages to the instrument cluster over the CAN data bus to control operation of certain park assist system audible warnings and textual messages displayed in the reconfigurable display of the instrument cluster.
The PAM receives battery current on a fused ignition switch output (run-start) circuit through a fuse in the Junction Block (JB) (also known as the interior Power Distribution Center/PDC or PDC-2). The module receives ground through a ground circuit and take out of the underbody wire harness. These connections allow the module to be operational whenever the status of the ignition switch is Start or On.
The hard wired circuits between components related to the park assist module 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 PAM or the electronic controls and 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 PAM 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.