Parking Assist Control Module: Description and Operation
The microprocessor in the park assist module contains the park assist system logic circuits. 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 microprocessor 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 park assist module microprocessor 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 park assist module receives battery current on a fused ignition switch output (run-start) circuit through a fuse in the Junction Block (JB). 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 ignition switch is in the START or ON positions.
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 park assist module 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 module or the electronic controls and communication related to park assist module operation requires the use of a diagnostic
scan tool. Refer to the appropriate diagnostic information.