2007 Commander XK Factory Service Manual 8 - ELECTRICAL

OPERATION

CHIME WARNING SYSTEM

The chime warning system operates on battery voltage received through a fuse in the Junction Block (JB) on a non-switched fused B(+) circuit so that the system may operate regardless of the ignition switch position. The chime warning system also monitors the ignition switch position so that some chime features are functional only with the ignition switch in the ON position, while others are functional regardless of the ignition switch position.

The chime warning system provides an audible indication to the vehicle operator or occupants under the following conditions:

The EMIC provides chime service for all available features in the chime warning system, except for the audible warning function provided by each of the optional park assist system display modules. The EMIC relies upon its internal programming, numerous hard wired inputs, and electronic message inputs received from other modules over the CAN data bus network to provide the chime warning system features. The internal programming of the EMIC determines the priority of each chime request input that is received, as well as the rate and duration of each chime that is to be generated.

The hard wired circuits between components related to the chime warning system 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 chime warning system or the electronic controls or communication between modules and other devices that provide some features of the chime warning system. The most reliable, efficient, and accurate means to diagnose the chime warning system or the electronic controls and communication related to chime warning system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

PARK ASSIST SYSTEM

The park assist system is active only when the ignition switch is in the ON or START positions, the parking brake is released and the vehicle speed is less than 16 kilometers-per-hour (10 miles- per-hour). In addition, the rear park assist system is active only with the manual or automatic transmission gear selector lever in the REVERSE position, while the front park assist system is only active with the automatic transmission gear selector lever in the DRIVE or REVERSE position or with the manual transmission selector lever in any position except REVERSE. In vehicles equipped with this option, the system is enabled from the factory as a default. Both systems can be manually disabled in unison by the vehicle operator using the park assist switch integral to the lower instrument panel switch pod. If the vehicle operator does not want the system active, momentarily depressing the park assist switch OFF button will disable the system until the switch button is depressed again.

Reasons for disabling the system include trailer towing and off road use. With a trailer attached to the vehicle the audible and visible rear park assist alerts would be incessant whenever the gear selector lever was in the REVERSE or NEUTRAL positions due to the proximity of the trailer to the rear of the vehicle. Similarly, operating the vehicle off road may cause the front and rear park assist alerts to become distracting due to the proximity of large trees or boulders and the extreme approach angles that may be encountered while maneuvering on off road trails or terrain. When the system is disabled, a PARK ASSIST DISABLED textual message will appear in the instrument cluster reconfigurable dot matrix display whenever the gear selector lever is in any position in which the system is normally active. An amber Light Emitting Diode (LED) indicator in the park assist switch button will also be illuminated whenever the ignition switch is in the ON position and the system is disabled.

The microprocessor based park assist module is the central component of the park assist system. It supplies voltage to the park assist sensors and the park assist displays, receives and analyzes data from the sensors, calculates and communicates the proper display information to the park assist displays, performs system diagnostics, and communicates with other electronic modules in the vehicle or with a diagnostic scan tool over the Controller Area Network (CAN) data bus. The module operates on battery voltage received through a fuse in the Junction Block (JB), and is grounded through a take out and eyelet terminal of the underbody wire harness that is secured by a nut to a ground stud on the rear floor panel just outboard of the module mounting location.

Ultrasonic park assist sensors in the front or rear bumper fascia allow the park assist system to locate and identify the proximity of nearby obstacles. These sensors each generate ultrasonic sound pulses when triggered by the park assist module, then signal the module when an echo of the reflected sound pulses is received. The detection distance range from the front or rear of the vehicle is about 0.3 meters (11.8 inches) to about 1.5 meters (59.1 inches), and the detection height range from the ground is about 0.2 meters (7.8 inches) to about 0.8 meters (31 inches). The detection area extends somewhat around both sides (corners) of the vehicle.

The park assist display units provide the vehicle operator with both visible and audible warnings indicating the relative range of a detected object. The front display is visible to the vehicle operator while looking forward. The rear display is visible to the vehicle operator over an inboard shoulder as they look rearward while backing the vehicle up, but is not visible in a properly adjusted inside rear view mirror while looking forward. Each display contains two sets of eight Light Emitting Diode (LED) indicator units, one set dedicated to each side of the vehicle, and an audible chime tone transducer. The LED units are concealed beneath a smoked oval lens and are not clearly visible when they are not illuminated. When the park assist system is active and no obstacles are detected, the two outermost, amber LED units in the display are illuminated at a reduced intensity to provide visual confirmation that the system is operating.

Each display provides a visual indication of a detected object by illuminating one or more LED indicators, amber first followed by red, moving toward the center of the display as the vehicle gets closer to the object. As the vehicle comes to within about 40 centimeters (31 inches) of the object, 1 red LED is illuminated and the display emits a series of short, intermittent, audible beeps. If the audio system is turned ON, the audio output will be muted automatically while the park assist audible warning is being generated. The audible warning changes from intermittent beeps to a continuous tone as the final red indicators are illuminated on 1 or both sides of the display and the vehicle comes to within 30.5 centimeters (12 inches) of a detected object.

When the park assist module monitors a problem in any of the park assist system circuits or components, it stores a fault code or Diagnostic Trouble Code (DTC) in its memory circuit, sends an electronic message to the instrument cluster, and a SERVICE PARK ASSIST SYSTEM textual message is displayed in the instrument cluster reconfigurable dot matrix display. See the owner's manual in the vehicle glove box for more information on the features, use and operation of the park assist system.

The hard wired circuits between components related to the park assist system 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 system 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 system 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.