Battery positive voltage is provided to the radio from RADIO AMP fuse in the fuse block - right instrument panel (I/P). The radio is grounded to G201. The radio is enabled/disabled by class 2 messages from the body control module (BCM). The BCM also allows for retained accessory power which allows the radio to operate for up to 10 minutes after the ignition is turned off. The radio can only be deactivated by one of the following conditions:

1. Front door is opened.
2. The 10 minute timer has elapsed.
3. Loss of state of health message from the BCM.

The entertainment system on this vehicle is configured with a base or uplevel system.

Both systems include a radio, antenna, and speakers.

The uplevel system provides the customer with enhanced audio system features. Digital radio reception is available as an option with all radio levels. The following list shows the Entertainment RPOs that are available for this vehicle:

Each item in the list represents topics covered in detail below:

Radio Signal

The radio signal is sent from a broadcast station and is then received by an antenna. The strength of the signal received depends on the following:

AM Reception

The AM band has a lower frequency range than the FM band. These longer wavelengths:

The AM frequencies have longer range due to the ground wave. The ground wave follows the curvature of the earth and is affected by its conductivity. Greater conductivity equates to less signal loss, thus transmission over water is better than over land. The AM band has a range of 80-320 km (50-200 mi).

FM Reception

The shorter wavelengths of the higher frequency FM band:

Broadcasts in the FM band are limited to "line of sight" reception which is typically 40 km (25 mi). Even when out of a direct line of sight, the signal may be reflected into areas that would be in a "shadow" otherwise. Factors which affect the line of sight include:

XM satellite radio provides digital radio reception. The XM signal is broadcast from two satellites and, where necessary, terrestrial repeaters. The high power satellites allow the antenna to receive the XM signal even when foliage and other partial obstructions block the antennas view of the satellite. Terrestrial repeaters are used in dense urban areas. These repeaters will receive the satellite signal and re-broadcast them at much higher power levels in order to ensure reception in areas with densely packed tall buildings.

The "Theftlock" theft deterrent system is a feature on all base and uplevel radios. There is no need to program a security code into the radio as in past model years. The theft deterrent system now utilizes class 2 serial data to determine if the radio is in the appropriate vehicle. Each time the radio receives the "run" power mode message, it compares the VIN information it has stored to the VIN information received from a module on the class 2 serial data circuit responsible for transmitting that information. If a mis-match occurs, the radio display will indicate to the user the radio is locked. Once this takes place, a DTC will set, the radio will not respond to any button presses and become inoperative. The two scenarios able to cause this condition are:

The only way to unlock the radio is by using a scan tool. Always refer to the table in this section to diagnose the "Theftlock" DTC for further information.

Some audio functions are available using the steering wheel controls. The steering wheel controls are actually a resistor network which consists of multiple momentary contact switches and a series of resistors. The switches and resistor network is arranged so that each switch has a different resistance value. When a switch is pressed, a voltage drop occurs in the resistor network which produces a specific voltage value unique to the switch selected. These specific voltage values allow the radio to identify which switch has been pressed. The radio responds just as if the corresponding radio front panel button had been pressed.

The radio supplies voltage to the steering wheel control switch via the radio on signal circuit. The specific voltage signal from the switch is returned to the radio on the remote radio control signal circuit.

XM is a national satellite radio service that offers up to 100 coast to coast channels including music, news, sports, talk and children's programming. XM provides digital quality audio and text information, including song title and artist name. A service fee is required in order to receive the XM service. For more information, contact XM at www.xmradio.com or call 1-800-852-9696.

Digital Radio Receiver

The radio controls communicate with the digital radio receiver via the class 2 communication circuit. The digital radio receiver sends remote radio audio signals to the radio.

Viewing Messages

Press the DISP or RCL button while in XM mode to view various pieces of information related to the current song or channel. By pressing and releasing the DISP or RCL button, you may view four different categories of information: Artist Name/Feature, Song/Program Title, Channel Category, and other Additional Information that may be broadcast on that channel. Additional Information messages may not always be available. If an Additional Information message is being broadcast on the tuned channel, the INFO icon will appear on the display. Each of the four information types may have multiple pages of text. To reach a category, press and release the DISP or RCL button consecutively until the desired type is displayed. If there are multiple pages of text for the selected information type, the radio will automatically display all the pages for that type at a rate of approximately one page every three seconds before timing out and returning to the default display. You may override this feature by pressing the DISP or RCL button to review all of the pages at your own pace.

The US8 radio will play both standard audio CDs and CD-Rs. The CD-Rs may contain standard audio format (*.cda) or compressed audio in the *.mp3 format.

Customers who make their own music CD-Rs should be aware of the following:

If these guidelines are not followed, a customer recorded CD may not play. Note that the radio has no ability to record *.mp3 files or any audio to a CD-R, it has only the ability to read information on a CD-R.