GM Service Manual Online
For 1990-2009 cars only
Table 1: Radio Features
Table 2: Cassette Features
Table 3: Compact Disc Features
Table 4: XM Advisory Messages

The Entertainment System on this vehicle is configured with either a base or an uplevel system. Both the base and uplevel systems contain a radio, antenna, speakers.

The following list shows the radios available for this vehicle:

    • Base Radio (UN0) - AM/FM Stereo, CD, with Auto Tone Control, and RDS
    • Uplevel Radio (UP0) - AM/FM Stereo, Cassette, CD, with Auto Tone Control, and RDS

Radio Features

Controls

Base CD UN0

Uplevel Cassette, CD UP0

Power

Push the PWR/VOL knob to turn the radio on.

Volume

The volume is adjusted by rotating the PWR/VOL knob.

Tune

Turn the TUNE knob.

Seek

Momentarily press the right or left SEEK button.

Scan

Hold one of the SEEK arrows for at least 2 seconds.

Presets

Six AM, Six FM1 and Six FM2. Six XM1 and Six XM2 if equipped with U2K.

Preset Scan

Steering wheel controls only.

Preset Saving

Press and hold the desired button until an audible beep is heard.

Set Clock

Press and hold the H until the correct hour appears. Press and hold the M button until the correct minute appears.

Recall

Press the DISP button.

Balance

Press the TUNE/AUDIO knob. Turn the knob to adjust.

Fade

Press the TUNE/AUDIO knob. Turn the knob to adjust.

Bass

Press the TUNE/AUDIO knob. Turn the knob to adjust.

Treble

Press the TUNE/AUDIO knob. Turn the knob to adjust.

Auto Tone Control

Press the TUNE/AUDIO knob. Turn the knob to adjust.

Cassette Features

Controls

Uplevel Cassette, CD UP0

Play

Press the CD/TAPE button to change to the tape function when the radio is on.

Stop

Press the AM/FM button to listen to the radio when a tape is in the player.

Eject

Press the eject button near the tape slot.

Forward

Press the right arrow button (preset 2).

Reverse

Press the left arrow button (preset 1).

Previous

Press the left SEEK button.

Next

Press the right SEEK button.

Changing Sides

Press the SIDE button to change the side of the tape that is playing (preset 6).

Compact Disc Features

Controls

Base CD UN0, and Uplevel Cassette, CD UP0

Play

Press the CD button to change to the CD function when the radio is on.

Stop

Press the AM/FM button to play the radio when a CD is loaded in the player.

Eject

Press the eject button near the CD slot.

Forward

Press the right arrow button (preset 2).

Reverse

Press the left arrow button (preset 1).

Random Order

Press the RDM button to hear the tracks in random order.

Recall

Press the DISP button.

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

    • Radio Reception
    • Diversity Antenna System
    • Theftlock
    • Radio Data System (RDS)
    • Steering Wheel Controls
    • XM Satellite Radio

AM/FM Reception

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:

    • The power output (wattage) of the broadcasting station
    • The location of the vehicle (or receiver) relative to the broadcast tower.
    • Obstacles between the tower and the receiver
    • Atmospheric conditions
    • What band (AM or FM) the station is broadcasting
    • Type of antenna and the ground plane

AM Reception

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

    • Bend around Obstacles
    • Follow the curvature of the earth
    • May reflect off the ionosphere (skip)

The AM frequencies have longer range due to the ground wave. The ground wave follows the curvature of the earth and is effected 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:

    • Reflect off obstacles
    • Are absorbed by the ground
    • Penetrate the ionosphere

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:

    • Height of the broadcast antenna
    • Height of the receiving antenna
    • Terrain and buildings in the broadcast path

XM Satellite Radio

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 ares. 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.

Diversity Antenna System

The diversity antenna system uses both front and back windows with an integral antenna built between the glass layers of the windshield and as an applique to the rear glass. Any damage to the antenna requires replacing the glass.

A diversity antenna system is designed to deliver the best radio signal reception possible. Two antennas are used to form a diversity system. The primary antenna is part of the rear window and looks similar to the defogger grid. This antenna receives both AM an FM signals. The secondary antenna is part of the front windshield and receives only FM signals.

The antenna reception signals are sorted out by the radio antenna module. The radio antenna module is enabled when the radio is turned on. When the AM or FM band is selected on the radio, the antenna module connects the rear window antenna directly to the radio. In addition, when the FM band is selected an enable signal is sent to the antenna module. Superimposed on this enable signal is the strength of the signal being received by the radio tuner. The antenna module now performs two functions. It switches between the front and rear antennas, monitoring the radio signal strength and combines both signals and phase aligns them to create one strong signal.

Theft Deterrent

Radio

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:

    • A radio is installed from another vehicle
    • A module which communicates on the class 2 serial data circuit which supplies VIN information to the radio is replaced and not properly setup with the correct VIN information for that vehicle.

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.

Digital Radio Receiver

The digital radio receiver utilizes class 2 serial data to determine if it is in the appropriate vehicle. Each time the digital radio receiver receives the "run" power mode message, it compares the VIN information received from a module which supplies VIN information on the class 2 serial data circuit. If a mis-match occurs, the radio display will indicate to the user the digital radio receiver is locked. The digital radio receiver cannot be unlocked, it must be replaced. The two scenarios able to cause this condition are:

  1. A digital radio receiver is installed from another vehicle
  2. A module which supplies VIN information is replaced and not properly setup with the correct VIN information for that vehicle

Radio Data System (RDS)

All uplevel audio systems are equipped with technology known as the Radio Data System (RDS). RDS is a system that sends data along with the audio of the FM station you are currently tuned to. RDS is a standard that defines how a FM broadcast station may send digital data along with the audio program. Think of it as a one way wireless modem, allowing the broadcaster to send information about his program to your receiver.

RDS data is carried in what is known as a "subcarrier". A subcarrier is a frequency that the FM broadcaster is authorized to use to send data or other audio programs that are not audible in the main audio program. RDS information can be used to display program information and to control the radio.

To receive the RDS signal, all that is needed is an FM receiver with a RDS circuit. A special integrated circuit capable of dealing with the RDS signal is in the RDS circuit and passes it along to the receiver's microprocessor where it is decoded and acted upon.

RDS Basic Information

RDS basic information:

    • RDS functions are provided in the FM broadcast band only.
    • RDS functions will only work with FM broadcast stations that are broadcasting RDS data.
    • Not all FM Broadcast stations broadcast RDS data or offer all of the RDS services.
    • RDS functions may not work properly when reception is weak, reception is of poor quality, or RDS is not implemented properly by the FM Broadcaster.

In some cases, a radio station broadcasting incorrect information may cause the RDS features of the radio to appear to work improperly.

Broadcast RDS information can be used in a variety of ways by the receiver and listener, but basically falls into two categories: Display and Control.

Displaying Program Information

RDS displays textual information such as:

    • The name of the station.
    • The type of program.
    • General information such as artist and song title, call in phone numbers, etc.

Finding an RDS Station

Press the P-TYP button, rotate the TUNE/AUDIO knob to select a program type, then press the left or right SEEK button. The radio will seek to the next RDS station of the selected program type. If none are available then NONE FOUND will appear on the display.

Using the RDS Traffic Feature

Some RDS broadcasters may carry traffic information programming to inform you of current traffic conditions in your listening area and is indicated by the TRAF icon in the radio display. RDS enables the broadcaster to get this information to you even when you are listening to a tape or compact disc. This feature can be enabled or disabled by the listener. Press the TRAF button to find a station that claims to carry traffic information. You may do this even when playing a cassette tape or compact disc. This action will operate in the background without interrupting the current playback. If the radio is not currently tuned to an RDS traffic station, the radio will immediately SEEK an RDS traffic station. If the radio finds an RDS traffic station, TRAF will appear in the radio display. If the radio cannot find an RDS traffic station after searching through the entire FM band, the radio will display "NO TRAFFIC".

Viewing Messages

When INFO appears on the radio display, a new message is available for viewing. These messages are from the RDS broadcaster and may be general information such as artist and song title. To view the text message, press the INFO button. If the whole message does not appear on the display, parts of the message will appear every three seconds until the message is completed. To view the message faster, press the INFO button again.

Steering Wheel Controls

Some audio functions are available using the steering wheel controls. The steering wheel controls consist of multiple momentary contact switches that connect a series of resistors. When a steering wheel control button is pressed, a specific resistance value is noted by the DIM. This results in a generated voltage, unique to the particular button. The DIM alerts the radio that the button has been pressed, and the radio responds, just as if the corresponding radio front panel button had been pressed.

Tape/CD Player Error Messages

The radio displays an error when any of the following occurs.

    • The radio will display error codes for the tape player and integral CD player.
    • The radio will display the following tape player error codes for tight tape, broken tape, and wrapped tape. If these conditions are detected, the radio will switch to the radio mode and eject the tape. The error code will be displayed for 5 seconds, followed by the tuner display, then the default.
       - E10-Tight tape.
       - E11-Broken tape.
       - E13-Communication problem.
       - E14-Wrapped tape.
    • The radio will display the following integral CD player error codes. If one of these problems is detected, the unit will switch to the radio mode and eject the CD. The display will show TOD, if the unit is off, or display the radio frequency for 5 seconds, then the default, if the unit is on.
       - E20-Optics focus error, may be due to moisture.
       - E21-Optics loss of tracking control, maybe due to blemishes on disc.
       - E22-Load/Unload motor problem.
       - E23-Communication problem.

XM Satellite Radio

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 low level audio signals to the audio amplifier.

Viewing Messages

Press the DISP button while in XM mode to view various pieces of information related to the current song or channel. By pressing and releasing the DISP 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, DISP 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 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 button to review all of the pages at your own pace.

Selecting a PTY

The TUNE/AUDIO knob can be used to scroll through the list of available program types (P-TYP). Press the P-TYP button, then rotate the TUNE/AUDIO knob to scroll through the available program types. When the desired program type is shown on the display, press the right or left SEEK button twice. The radio will seek the next station of that type.

XM Advisory Messages

Radio Display Message

Condition

XM Updating

Updating encryption code

No XM Signal

Loss of signal

Loading XM

Acquiring channel audio (after 4 second delay)

Channel Off Air

Channel not in service

Channel Unavail

Channel no longer available

No Artist Info

Artist Name/Feature not available

No Title Info

Song/Program Title not available

No CAT Info

Category name not available

Not Found

No channel available for the chosen category

No Information

No text/informational message available

XM Theftlocked

Theft Lock active

XM Radio ID

Electronic serial number (ESN) channel 0

Unknown

Radio ID not known (should only be if hardware failure

Check XM Receiver

Hardware failure