Rear Only Parking Aid Camera: Operation
Image Display
The rear parking aid camera image is displayed by the interior rear view mirror, FCDIM, or FDIM when reverse gear is selected. To enable the display when reverse gear is selected for vehicles with an interior rear view mirror display, the mirror is receives voltage from the BCM on the reverse lamps circuit. To determine the selector lever position and enable the camera display on all other vehicles, the PCM sends the gear position message to the GWM on the HS-CAN1. The GWM then sends the message to the APIM or FCDIM via the HS-CAN3.
The camera is on any time it receives voltage (when the ignition is ON), but a video signal is only generated under certain conditions. When reverse gear is selected, the camera continuously generates a video signal. When any gear except reverse is selected, the camera turns the video signal off when the vehicle speed reaches 16 km/h (10 mph), and turns the video signal on when vehicle speed falls below 8 km/h (5 mph). If the camera is not configured properly, some features may be inoperative. The camera sends the video signal on shielded twisted pair wires directly to the display.
The following parking aid camera system features are driver selectable:
- Visual park aid alert - assists the driver to visually see the object causing the parking aid system to sound. (centerstack infotainment display only)
- Manual zoom - allows the driver to manually zoom the image. (centerstack infotainment display only)
- Video delay - allows the driver to see the image behind the vehicle after the vehicle is shifted out of reverse into any gear other than park.
The following camera system features are not driver selectable:
- Fixed guidelines - assists the driver with aligning the vehicle with an object.
- Active guidelines - displays the intended path of the vehicle based upon steering wheel input.
On vehicles equipped with a centerstack infotainment display, the display settings menu is used to turn the visual park aid alert and video delay on and off. The visual park aid alert and video delay features are generated within the FCDIM or APIM.
To turn the manual zoom feature on and off, the driver uses an on screen button while reverse gear is selected. The driver generated commands originate at the FDIM (which is hardwired to the APIM), or FCDIM. The APIM or FCDIM sends the driver generated commands over the HS-CAN3 to the GWM. The GWM then sends the commands to the BCM on the HS-CAN1. The BCM sends the zoom command to the rear parking aid camera via the LIN circuit. The zoom is generated by the rear parking aid camera.
The fixed and active guidelines are generated by the rear parking aid camera and are not selectable by the driver.
LIN Communication
The BCM and the rear parking aid camera communicate via a LIN circuit which is a dedicated single wire communication network. The BCM is the master module on the LIN, and it sets and stores Diagnostic Trouble Codes (DTCs) for the rear parking aid camera and the communication network.
The messages sent from the BCM to the camera are:
- Camera configuration data
- Display manual zoom request
- Guideline on/off request
- Liftgate ajar status
- Trailer connection status (if equipped with factory trailer tow)
- Steering angle
- Standby enable/disable request
The messages sent from the camera to the BCM are:
- Camera status
- Display zoom status
- Camera part number data
- Guideline status
Visual Park Aid Alert
The visual park aid alert feature displays a visual highlight in the zone where an object has been detected by the rear parking aid system. This feature utilizes the parking aid sensor data from the PAM to generate the visual highlights on the video image. When reverse gear is selected and an object is detected by a rear parking aid sensor, the parking aid sensor data message from the PAM is used by the APIM or FCDIM to generate the alert.
If the visual park aid alert feature is enabled, the feature is still operational even if the rear parking aid system has been disabled by the driver.
Fixed Guidelines
The video camera fixed guidelines feature displays guidelines on top of the video image to assist the driver with alignment of the vehicle. A dashed line on the displayed image represents the center of the vehicle and 3 color-coded lines (red, yellow, green) identify different zones between the rear of the vehicle and objects.
The guidelines are not shown when reverse is not selected (video delay active).
If the vehicle is equipped with a factory TRM, the fixed guidelines are not shown when a trailer is electrically connected to the vehicle.
Active Guidelines
If the guidelines remain inoperative, it may be necessary to disconnect the battery for 5 minutes with the driver's door open, then drive the vehicle for 8 kilometers (5 miles) in normal city driving before performing the procedure described above.
The active guidelines feature displays dynamic guidelines that correspond to the projected path of vehicle travel, based on the current steering angle. Several modules are involved in generating the steering angle data used to support the active guidelines. The SCCM (vehicles without adaptive steering) or SASM (vehicles with adaptive steering) monitors the steering angle sensor and sends the steering wheel angle sensor data to the ABS module via the HS-CAN2. The ABS module uses this message to generate the steering angle message that is sent to the GWM on the HS-CAN2. The GWM then sends the message to the BCM via the HS-CAN1. The BCM sends the steering angle data to the rear parking aid camera via the LIN circuit. The camera uses this data to generate the active guidelines over the video image.
If the steering wheel is in the straight-ahead position or if the liftgate is open, the active guidelines are not shown.
The guidelines are not shown when reverse is not selected (video delay active).
If the vehicle is equipped with a factory TRM, the active guidelines are not shown when a trailer is electrically connected to the vehicle.
Manual Zoom
The manual zoom feature is generated by the rear parking aid camera and has one level of zoom. If the manual zoom feature is on and the vehicle is shifted out of reverse gear, the manual zoom feature is disabled and must be re-enabled the next time reverse gear is selected. When the driver turns the zoom on or off at the display, the zoom command is sent from the FCDIM or APIM through HS-CAN3 to the GWM then over HS-CAN1 to the BCM. The BCM then sends the manual zoom request message to the rear parking aid camera via the LIN circuit.
Video Delay
When the video delay is turned on, the display keeps the rear video display enabled after the transmission is shifted out of reverse gear into any gear other than park, until the vehicle speed reaches 8 km/h (5 mph). With the delay off (default), the image displays until the transmission is shifted out of reverse gear.