Rear Park Assist (RPA)

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

The RPA system is active only when the status of the ignition is ON, the transmission gear selector lever is in the Reverse (R ) position and the vehicle speed is less than about 11 km/h (7 mph). The system can be manually disabled and enabled by the vehicle operator using the park assist OFF push button in the instrument panel switch pod. In vehicles equipped with this option, the system is enabled from the factory as a default.

Reasons for disabling the system include trailer towing and off road use. With a trailer attached to the vehicle the audible and visual RPA alerts would be incessant whenever the gear selector lever was in the Reverse (R ) position due to the Proximity of the trailer to the rear of the vehicle. Similarly, operating the vehicle off road may cause the RPA 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 SYSTEM OFF graphic and textual message will appear in the EVIC display of the IPC at the beginning of each ignition ON cycle, and whenever the gear selector lever is in the Reverse (R ) position. When the system is enabled, a PARK ASSIST SYSTEM ON graphic and textual message will appear in the EVIC display of the IPC at the beginning of each ignition ON cycle, and a PARK ASSIST READY graphic and textual message will appear in the display whenever the gear selector lever is in the Reverse (R ) position.

The microcontroller based, 4 channel PAM is the central component of the RPA 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 EVIC display, calculates and communicates the proper audible outputs to the RRM, performs system diagnostics and communicates with other electronic modules in the vehicle or with a diagnostic scan tool over the CAN data bus. The PAM operates on battery voltage received through a fused ignition (RUN) fuse in the Power Distribution Center (PDC) and is grounded through a take out of the body wire harness secured to the body sheet metal.

Four ultrasonic park assist sensors in the rear bumper fascia allow the RPA system to locate and identify the Proximity of nearby obstacles. These sensors each generate ultrasonic sound pulses when triggered by the PAM, then signal the PAM when an echo of the reflected sound pulses is received. The detection distance range from the rear of the vehicle is about 2 m (80 in), and the detection height range from the ground is about 0.2 m (7.8 in) to about 0.8 m (31 in). The detection area extends somewhat around both rear corners of the vehicle.

The EVIC display provides the vehicle operator with a graphical representation of the vehicle along with numerous illuminated arc sections that indicate the relative location and range of detected objects. The display is visible directly in front of the vehicle operator and operates based upon the electronic message inputs received from the PAM over the CAN data bus. There are three regions at the rear of the vehicle designated for arc alerts: Center, Left and Right. The Center region consists of six zones, while the Right and Left regions consist of two zones. The zones range from furthest to nearest from the rear of the vehicle. The arc sections are illuminated in an amber color until the nearest zone is reached, at which point the arc sections become illuminated red in color.

Meanwhile, the RRM generates audible indications of a detected object by emitting a series of chime tones that grow progressively higher in frequency as the vehicle gets closer to the object. As the vehicle comes within about 30 centimeters (12 inches) of the object, the audible warning changes from a high frequency series of chime tones to a single continuous tone. If the audio system is active when the RRM receives a chime request message from the PAM, the audio output will be muted automatically while the RPA audible warnings are being generated.

When the PAM monitors a problem in any of the RPA system circuits or components, it stores a fault code or Diagnostic Trouble Code (DTC) in its memory circuit, sends an electronic message to the EVIC and the EVIC displays a graphic with a SERVICE PARK ASSIST SYSTEM textual message. If the PAM detects that the park assist sensors are inoperative due to an accumulation of road film, mud, ice or snow on the rear fascia, the EVIC will display a WIPE OFF REAR PARK ASSIST SENSORS graphic and textual message. When the system is disabled by the PAM due to a detected external error or influence, a PARK ASSIST SYSTEM DISABLED graphic and textual message will appear in the EVIC display of the IPC whenever a new ignition cycle begins and each time the gear selector lever is in the Reverse (R ) position.