Module, Park Assist (PAM): Operation

WARNING: This page is about a different car, the 2020 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

The microcontroller within the Park Assist Module (PAM) contains the park assist system logic circuits. The PAM 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 data link connector located on the driver side lower edge of the instrument panel.

The PAM provides source current to the park assist sensors located on the bumper fascia or fascias. The PAM then monitors return inputs from each of the sensors on dedicated hardwired data communication circuits. These sensor inputs allow the PAM to determine when an obstacle is in the path of the vehicle, to calculate the relative location of an obstacle and to determine whether the distance to that obstacle is increasing or decreasing.

Pre-programmed decision algorithms and calibrations allow the PAM 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 PAM sends electronic messages to the Instrument Panel Cluster (IPC) and the Radio over the CAN data bus to obtain the proper park assist system visual and audible outputs.

In vehicles equipped with an automatic transmission and the optional Front and Rear Park Assist (FRPA) or the Parallel and Perpendicular Park Assist (PPPA), the PAM also communicates with the Antilock Brake System (ABS) module using electronic messaging over the CAN data bus to provide the autonomous brake (also known as brake and release) warning feature. In vehicles equipped with the optional PPPA, the PAM also communicates with the Electronic Power Steering (EPS) module using electronic messaging over the CAN data bus to provide the semiautomatic parallel and perpendicular parking features.

While the system is active, the PAM microcontroller continuously monitors all of the park assist system electrical circuits and components to determine the system readiness. If a monitored system fault is detected, the PAM sets a Diagnostic Trouble Code (DTC) and sends the appropriate electronic messages to the IPC to control the display of the appropriate park assist system graphics and textual messages in the Electronic Vehicle Information Center (EVIC) display within the IPC and the generation of the appropriate audible warnings by the IPC.

The PAM receives battery current on a fused ignition output (run) circuit through the Power Distribution Center (PDC). The PAM has a path to ground at all times through a ground circuit and take out of the body wire harness that is secured to the body sheet metal. These connections allow the PAM to be operational whenever the status of the ignition switch is ON.

The hardwired circuits between components related to the PAM may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, 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 DIAGNOSTIC CODE INDEX .