GM Service Manual Online
For 1990-2009 cars only

Battery positive voltage is provided to the radio from the RADIO BATT fuse in the fuse block-right I/P. The radio is grounded via G202 and G203. The radio is enabled/disabled by class 2 messages from the body control module (BCM). The BCM contains an audio delay timer which allows the radio to operate for up to 10 minutes after the ignition is turned off. The radio is deactivated by one of the following actions:

  1. Driver door is open.
  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 and uplevel system. The base and uplevel systems contain a radio, antenna, speakers, and on some vehicle lines an audio amplifier.

The uplevel system differs from the base system by providing the customer with enhanced audio system features. Some of those features may include the radio data system (RDS), an audio amplifier and programmable equalizer (EQ).

The following list shows the radios available for this vehicle:

    • Base Radio (UM6) - AM/FM Stereo and Cassette
    • Uplevel Radio (U1P) - AM/FM Stereo, CD, EQ and RDS
    • Uplevel Radio (U1Q) - AM/FM Stereo, Cassette, CD, EQ and RDS

Features

Controls

Base UM6

Uplevel U1P

Uplevel U1Q

Radio Features

Power

Push PWR/VOL knob to turn the radio on.

Push Power knob to turn the radio on.

Volume

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

The volume is adjusted by rotating the Volume knob.

Speed Compensated Volume (SCV)

N/A

Press the SCV button.

Adjust the SCV by pressing SCV until the desired volume setting appears on the display. Three settings are available; LOW, MEDIUM, and HIGH.

Tune

Turn the RCL/TUNE knob.

Turn the TUNE knob.

Seek

Press the right or left arrow on SEEK button.

Momentarily press SEEK/SCAN button.

Scan

Press the right or left arrow on SEEK button.

Hold SEEK/SCAN button at least 4 seconds.

Presets

Six AM, Six FM1 and Six FM2

Preset Saving

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

Preset Scan

Press and hold the SEEK button at least 4 seconds until PSCAN and the preset number are displayed. A double beep is also heard.

Set Clock

Press and hold the HR or MN button until an audible beep indicates the time set mode has been entered. Once the beep is heard, the time can be set by tapping each button to incrementally adjust the time. Holding down each button will rapidly change the time.

Recall

Push the RCL/TUNE knob.

Push the TUNE knob.

Mute

Steering Wheel Control only.

Press the MUTE button to silence the system. Press it again, or any other radio button, to turn on the sound.

Fade or Balance

Press the AUDIO button, press the up or down arrow to select.

    • Pontiac (U1P & U1Q) and Olds (U1Q) - Press the TONE button to select and adjust with the SELECT knob.
    • Olds (U1P) - Press the AUDIO button to select and adjust with knob above button.

Bass, Treble or Midrange

Press the AUDIO button, press the up or down arrow to select.

    • Pontiac (U1P & U1Q) and Olds (U1Q) - Press the TONE button to select and adjust with the SELECT knob.
    • Olds (U1P) - Press the AUDIO button to select and adjust with knob above button.

Programmable Equalizer

N/A

Press the AUTO EQ or EQ button to choose and program preset bass and treble equalization settings.

Cassette Features

Play/Stop

TAPE button

N/A

CD TAPE button

Eject

Eject button

Eject button

Forward

Preset button 4

Pontiac-preset button 1

Olds-preset button 2

Side

Press preset button 5 to play other side of tape.

Press the following button to play other side of tape:

    • Pontiac-preset button 2
    • Olds-preset button 5

Dolby Sound

N/A

Press preset button 6 to turn Dolby on or off.

Reverse

Preset button 3

Pontiac-preset button 4

Olds-preset button 1

Auto Reverse

Yes

Yes

Previous

Preset button 1 or left arrow on SEEK button.

Press the up or down arrow on the SEEK button.

Next

Preset button 2 or right arrow on SEEK button.

Press the up or down arrow on the SEEK button.

Compact Disc Features

Play/Stop

N/A

CD AUX button

CD TAPE button

Eject

Eject button

Forward

Pontiac-preset button 1

Olds-preset button 2

Reverse

Pontiac-preset button 4

Olds-preset button 1

Previous

Press the down arrow on the SEEK button.

Next

Press the up arrow on the SEEK button.

Random

Pontiac-preset button 3

Olds-preset button 4

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

    • AM/FM Reception
    • Antenna
    • Audio Amplifier
    • Theft Deterrent
    • Remote Playback Device
    • Radio Data System (RDS)
    • Radio Chime Level Adjustment
    • Steering Wheel Controls
    • Tape/CD Player Error Messages

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 40km (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

Antenna

There are two types of antenna systems available:

    • A fixed mast which is mounted on the body of the vehicle. Mast antennas are located typically on the fender or rear quarter panel of the vehicle.
    • A rear window defogger grid. This system uses the existing rear defogger grids as an antenna. Using the defogger as an antenna requires circuitry to decouple the RF from the DC heater current. This is accomplished by the radio antenna module.

Audio Amplifier

The purpose of an amplifier is to increase the power of a voltage or current signal. The output signal of an amplifier may consist of the same frequencies as the input signal or it may consist of only a portion of the frequencies of the input signal, as in the case of a subwoofer or a mid-range amplifier.

When the radio is turned on, the radio sends a voltage signal to the audio amplifier via the radio on signal circuit. The gain control signal circuit allows the radio to recognize that an amplifier is present. Once the radio detects the amplifier, the radio will output low level audio signals to the amplifier. With the amplifier enabled, the signal that drives the speaker is now amplified.

Theft Deterrent

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:

  1. A radio is installed from another vehicle
  2. 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.

Remote Playback Device

The remote playback device is either installed at the factory or in some instances it is dealer installed. There are three types of remote playback devices, a multi disc remote CD changer, a single disc CD player and a cassette player. All three devices have a wiring harness which plugs into the back of the radio. The radio controls and communicates with the remote playback device through a Entertainment and Comfort (E&C) or Class 2 communication circuit.

Remote CD Changer (CDX)

The remote CD changer allows for multiple compact disks to be played continuously without having to manually change compact discs. Normal size discs may be played using the slots supplied in the magazine. The magazine must first be loaded with discs before it can played. To load CD's, insert the CD's from bottom to top, placing the discs in the magazine label side up. If a disc is loaded label side down, the disc will not play and an error will occur. Care should be used to align and insert the disc into one disc tray only. Repeat this procedure for loading all of the discs in the magazine. Once the discs are loaded into the magazine, push the magazine into the changer in the direction of the arrow marked on the magazine. When the CD magazine is loaded, the changer will begin checking for discs in the magazine. This will continue for up to one and a half minutes, depending on the number of discs loaded. To eject the magazine from the player, push the CD changer door. The door will open. Then press the eject button. NOTICE: If the CD magazine fails to eject after the EJECT button has been pressed, do not attempt to pry the magazine from the CD changer. Whenever a CD magazine with discs is loaded in the changer, the CD changer symbol will appear on the radio display. If the CD changer is checking the magazine for CD's, the CD symbol will flash on the display until the changer is ready to play.

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 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.

Displaying RDS Information

The RDS feature is always on. When tuned to a non-RDS station, the radio will display frequency information as you would normally expect. When tuned to a RDS station, the radio can operate as follows:

    • The radio will change from displaying the frequency of the FM station to displaying the call letters of the station or display the nickname of the station.
    • Display the type of program.
    • Display general information such as artist and song title, call in phone numbers, etc.

Viewing and Selecting RDS Information for Display

Press the TUNE knob once for less then 2 seconds when the radio displays the program service (PS) name and the frequency of the station will be displayed. Press the knob again, and the program type (P-Type) will be displayed. Pressed again, and the program type (PTY) name will be displayed (if the broadcaster is broadcasting one). The PTY name is an eight-character name that the broadcaster may use to further identify the type of programming currently being broadcast. Should you decide that Frequency, P-Type or PTY name is more desirable to display when tuned to an RDS station than the PS name, press the TUNE knob until the desired information is displayed, then press and hold for more than 2 seconds. A beep should be heard and the radio will now display the selected information whenever tuned to an RDS broadcaster. The radio will display frequency for all non-RDS broadcast stations.

Using RDS Program Types to Tune Radio

Listed are several ways on how to tune your radio using RDS program types.

The radio will now be configured to tune based on RDS data rather than frequency.

A Fast Way to Find a RDS Station In Your Listening Area

  1. Press the PROG TYPE or P-TYPE button, the radio displays the current P-Type to search for.
  2. Rotate the TUNE SELECT RCL knob until the radio displays "ANY TYPE". Press the SEEK SCAN button again and the radio will now seek the first RDS Broadcaster of any kind that it can find in the FM band.

Finding a RDS Station By Specific Program Type

  1. Press the PROG TYPE or P-TYPE button, the radio will display the current P-Type to search for.
  2. Rotate the TUNE SELECT RCL knob until the desired program type is shown in the display.
  3. Press the SEEK SCAN button and the radio will now seek the first RDS Broadcaster of the selected P-Type.

If the radio cannot find the desired P-Type, the radio displays "NOT FOUND" and will return to the last station you were listening to.

Using the INFO Feature

When the INFO icon appears in the radio display, a new text message is available for viewing. These text messages are from the RDS broadcaster to the listening public and may be general information such as artist and song title, call in phone numbers, etc.

How to view the INFO message

    • To view the message when the INFO icon appears, press the INFO button to display the text message. If you do not press the INFO button again, the text message will automatically be displayed 8 characters at a time, 3 seconds between updates.
    • To view the text message faster, press the INFO button for less than 1 second to scroll through the message at your own speed.
    • The INFO icon disappears as soon as you press the INFO button. The INFO icon will appear when a new different message is received.
    • To view the most recent received message, press the INFO icon at any time even if the icon does not appear in the display.

Controlling the Radio

RDS can control the radio when data the receiver can use responds to timely information performing the following:

    • Interrupt the playback of your cassette or CD for traffic or emergency bulletins.
    • Search for stations by type of program.
    • Automatically follow networked programming from transmitter to transmitter as you travel from one listening area to another.
    • Set your clock to the time that the RDS Broadcast station broadcasts.

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, the "TRAF" icon will appear on the radio display as will brackets around the [TRAF] icon. If the radio cannot find an RDS traffic station after searching through the entire FM band, the radio will display "NO TRAFFIC".

Traffic Interrupt Feature

Whenever the TRAF icon is displayed, the current FM station may also broadcast traffic announcements. Traffic announcements are reports of the current traffic conditions in the listening area of the tuned FM broadcasters.

Your radio can interrupt the playback of a cassette or compact disc by use of the traffic interrupt feature. The traffic interrupt feature is enabled when the TRAF icon is displayed.

If the broadcaster sends out a traffic announcement while you are listening to FM or in the playback mode, "TRAFFIC" will be displayed on the radio and the audio from the broadcaster will be heard. At the conclusion of the traffic announcement, the radio will return to the previous playback mode.

During the time the radio displays "TRAFFIC" , you can adjust the volume of the traffic announcement. This will be the volume at which all future traffic announcements will be heard until the volume during another traffic announcement.

You can also interrupt a traffic announcement interrupt by pressing the TRAF button.

RDS Program Type Interrupts

When the Program Type feature is on, all program types may be selected as interrupts. Perform the following to select a program type as an interrupt.

  1. Turn ON the radio.
  2. Select the program type.
  3. Press and hold the program type button (labeled PROG TYPE or P-TYPE) for two seconds while the program type is displayed.

When an interrupt is set, the display shows the program type followed by an asterisk and the brackets around the [P-TYPE] icon are illuminated.

To turn an interrupt off:

  1. Select a program type marked as an interrupt.
  2. Press and hold the program type button (labeled PROG TYPE or P-TYPE) for two seconds. The program type will be unmarked by turning off the asterisk. If no other program type interrupts are set, the brackets around the [P-TYPE] icon are also turned off.

When a Program Type Interrupt is set, the radio will wait for the current FM RDS station to change its program type to one of those selected as an interrupt. When the station program type changes to a program type interrupt setting then the interrupt is activated. If the radio is in a playback mode, an interrupt will cause the radio to switch to the FM band, display the program type followed by "INT", and adjust the volume to the last active interrupt volume. If the radio is in the FM mode when an interrupt occurs, only the volume will change. The radio resumes the mode that was active prior to the interrupt, when an interrupt ends. An interrupt in progress may be canceled by pressing the program type button or a mode button.

During a national or local emergency, a special program type interrupt message "ALERT!" is displayed. This special announcement will cancel all other RDS features that are in progress, such as a traffic announcement.

Alternate Frequency (AF) Switching

RDS permits broadcaster's to send information to the radio that allows the radio to automatically switch frequency to the best quality station in that broadcaster's network.

Since the radio is displaying the broadcaster call letters or nickname, the listener will not see the frequency during an AF switch unless you have changed the default display to be frequency instead of Program Service name.

To enable or disable AF switching perform the following:

    • Press and hold the AM/FM button for two seconds or more.
    • The radio will display AF ON or AF OFF depending on the current condition of AF and a confirmation beep will be heard.

When AF is enabled and you recall a RDS station stored on preset, the radio determines if the station stored is of acceptable quality. If not, the radio checks all available AF's for your station. If the radio fails to locate your program, AF SEARCH will be displayed as the radio scans across the band looking for your program or an affiliated network. If the radio cannot find the original station or an acceptable alternate frequency NOT FOUND will be displayed and the radio returns to the original frequency for the preset.

RDS Clock Time

Broadcasters can choose to send clock time information in the RDS data. This information can be used to update the clock time on the radio. RDS clock time is broadcasted once a minute. To set the clock using RDS clock data perform the following:

    • Press and hold the HR and MIN buttons together for two or more seconds to update the time.
    • The display will show UPDATED after receiving the broadcasted time data.
    • If the broadcaster is not broadcasting the time data, the radio will display NO UPDATE and the time remains unchanged.

Radio Chime Level Adjustment

The radio is the vehicle chime producer which is only available on radios equipped with RDS. The chime is audible from the driver's side front door speakers.

To adjust the chime level louder.

  1. Turn ON the ignition.
  2. Turn OFF the radio.
  3. Press and hold preset button 6.

The chime volume level will change from the normal level to loud. The radio displays "LOUD".

To change back to the default or normal setting follow the previous steps. The chime volume level will change from the loud level to normal. The radio displays "NORMAL".

Each time the chime volume is changed, the radio sounds three chimes as an example of the new volume selected.

Steering Wheel Controls

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 remote radio control head supply voltage circuit. The specific voltage signal from the switch is returned to the radio on the steering wheel controls signal circuit.

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.
       - 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, maybe due to moisture.
       - E21-Optics loss of tracking control, maybe due to blemishes on disc.
       - E22-Load/Unload motor problem.
       - E23-Communication problem.