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

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, and speakers.

The uplevel system differs from the base level system by providing the customer with enhanced audio system features. Some of those features include an audio amplifier and more speakers.

The following list shows the radios available for this vehicle:

    •  Base Radio (UM7) - AM/FM Stereo
    •  Base Radio (UN6) - AM/FM Stereo, and Cassette
    •  Uplevel Radio (UL0) - AM/FM Stereo, Cassette, and EQ
    •  Uplevel Radio (UN0) - AM/FM Stereo, Cassette, CD, and EQ

Radio Features

Controls

Base UM7

Base UN6

Uplevel UL0

Uplevel UP0

Power

Rotate the VOLUME knob clockwise to turn the radio on. Rotate fully counterclockwise to turn radio off.

Push the VOLUME knob to turn the radio on or off.

Volume

The volume is adjusted by rotating the VOLUME knob.

Tune

Turn the TUNE knob.

Push the TUNE up or down arrow.

Seek

Push the SEEK left or right arrow.

Push the SEEK up or down arrow.

Presets

Six AM, Six FM1 and Six FM2

Preset Saving

Press and hold one of the numbered buttons for 4 seconds. The sound will mute and return.

Preset Scan

Press P SCAN to enable or disable preset scan.

Set Clock

Press and hold the HRS button until the correct hour appears. Press and hold MIN until the correct minute appears.

Recall

Push the VOLUME knob.

Push the RECALL button.

Balance or Fade

Rotate the control behind the VOLUME or TUNE knob to adjust.

Press the BAL or FADE button lightly so it extends. Turn the knob to adjust, then push the knob back in.

Bass or Treble

Press the BASS or TREB knob lightly so it extends. Turn the knob to adjust, then push the knob back in.

Equalizer

N/A

Press the TONE button to select one of the preset equalization settings.

Cassette Features

Controls

Base UM7

Base UN6

Uplevel UL0

Uplevel UP0

Play/Stop

N/A

Press the EJECT button to stop tape playback.

Eject

Press the EJECT button to remove the tape when it is not playing.

Forward

Press preset button 4.

Side

Press preset button 5.

Dolby® Sound

Press preset button 6.

Reverse

Press preset button 3.

Previous

Press preset button 1.

Next

Press preset button 2.

Auto Reverse

YES

Compact Disc Features

Controls

Base UM7

Base UN6

Uplevel UL0

Uplevel UP0

Play/Stop

N/A

Press the EJECT button to stop CD playback.

Eject

Press the EJECT button to remove the CD when it is not playing.

Forward

Press preset button 4.

Reverse

Press preset button 3.

Previous

Press preset button 1.

Next

Press preset button 2.

Random

Press preset button 6.

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, or 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
    • Which 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, or skip, off of the ionosphere

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:

    • 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

Antenna

The antenna systems available on this vehicle are fixed mast, and a passive rear window grid.

Audio Amplifier

The purpose of an audio 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.

Power is supplied to the amplifier from the RADIO PREM SOUND fuse in the Fuse Block-I/P. Ground is provided via G203. When the radio is turned on, the radio sends voltage signal to the amplifier via the amplifier present signal. This enables the audio amplifier to amplify the low level audio signals from the radio. The audio amplifier then sends the speaker output to the appropriate speaker.

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 fuse in the Fuse Block-I/P provides accessory voltage to the steering wheel controls. The specific voltage signal from the switches is sent to the radio via the steering wheel controls signal circuit.

Theft Deterrent Feature

The radio has this feature if it shows THEFTLOCK on its face. THEFTLOCK® is designed to discourage theft of the radio. It works by using a secret code to disable all radio functions whenever battery power is removed.

If THEFTLOCK® is active, the THEFTLOCK® indicator will flash when the ignition if OFF.

The THEFTLOCK® feature for the radio may be used or ignored. If ignored, the system plays normally and the radio is not protected by the feature. If THEFTLOCK® is activated, the radio will not operate if stolen.

When THEFTLOCK® is activated, the radio will display LOC to indicate a locked condition anytime the battery power is removed. If the battery loses power for any reason, you must unlock the radio with the secret code before it will operate.

Activating the Theft Deterrent Feature

The instructions which follow explain how to enter a secret code to activate the THEFTLOCK® system. It is recommended that you read through all nine steps before starting the procedure.

  1. Write down any 3 or 4-digit number from 000 to 1999 and keep it in a safe place separate from the vehicle.
  2. Important: If you allow more than 15 seconds to elapse between any of the steps, the radio display will automatically revert to time and you must start the procedure over at Step 4.

  3. Turn the ignition to the ACC or RUN position.
  4. Turn the radio off.
  5. Press the 1 and 4 buttons together. Hold them down until - - - shows on the display. Next you will use the secret code number which has been written down.
  6. Press MIN and 000 will appear on the display.
  7. Press MIN again to make the last 2 digits agree with the code.
  8. Press HR to make the first 1 or 2 digits agree with the code.
  9. Press AM-FM after you have confirmed that the code matches the secret code that was written down. The display will show REP to let you know that you need to repeat steps 5 through 7 to confirm the secret code.
  10. Press AM-FM and this time the display will show SEC to let you know that the radio is secure. The indicator by the volume control will begin flashing when the ignition is turned OFF.

Unlocking the Theft Deterrent Feature after a Power Loss

Enter the secret code as follows, pausing no more than 15 seconds between steps:

  1. LOC appears when the ignition is ON.
  2. Press MIN and 000 will appear on the display.
  3. Press MIN again to make the last 2 digits agree with the code.
  4. Press HR to make the first 1 or 2 digits agree with the code.
  5. Press AM-FM after you have confirmed that the code matches the secret code that was written down. The display will show SEC, indicating the radio is now operable and secure.

If you enter the wrong code 8 times, INOP will appear on the display. You will have to wait an hour with the ignition ON before you can try again. When you try again, you will only have 3 chances to enter the correct code before INOP appears.

Disabling the Theft Deterrent Feature

Enter the secret code as follows, pausing no more than 15 seconds between steps:

  1. Turn the ignition to the ACC or RUN position.
  2. Turn the radio off.
  3. Press the 1 and 4 buttons together, Hold them down until SEC shows on the display.
  4. Press MIN and 000 will appear on the display.
  5. Press MIN again to make the last 2 digits agree with the code.
  6. Press HR to make the first 1 or 2 digits agree with the code.
  7. Press AM-FM after you have confirmed that the code matches the secret code that was written down. The display will show - - -, indicating that the radio is no longer secured.

If the code entered is incorrect, SEC will appear on the display. The radio will remain secured until the correct code is entered.

When battery power is given to a secured radio, the radio will not turn on and LOC will appear on the display.

Removing the Customers Code

Important: Either the customers code or the factory backup code can be used in order to remove the customers code.

Perform the following steps in order to remove the customers code:

  1. Turn the ignition to the ACC or RUN position.
  2. Turn the radio OFF.
  3. Important: If the display changes to -- -- -- the theft deterrent is deactivated and no code is stored.

  4. Press and hold pushbuttons 1 and 4 for approximately 6 seconds until the display changes to SEC.
  5. Press the HR button.
  6. Set the first 2 digits (0-19) of the code with the HR button.
  7. Set the next 2 digits (0-99) of the code with the MIN button.
  8. Press the AM-FM button in order to enter the code.
  9. The theft deterrent is de-activated when -- -- -- is displayed and then the clock is displayed.

Adding the Customers Code

Perform the following steps in order to add the customers code:

  1. Turn the ignition to the ACC or RUN position.
  2. Turn the radio OFF.
  3. Important: If SEC is displayed the theft deterrent feature is already activated. Remove the old code before entering the new code.

  4. Press and hold the pushbuttons 1 and 4 for approximately 6 seconds until the display changes to -- -- --.
  5. Press the HR button.
  6. Set the first 2 digits (0-19) of the code with the HR button.
  7. Set the next 2 digits (0-99) with the MIN button.
  8. Press the AM-FM button in order to enter the code.
  9. Repeat steps 3-5 when REP then 00 are displayed. This will confirm the following:
  10. • The customers code
    • Activates the theft deterrent feature
    • After step 5, will display SEC in order to show the theft deterrent feature has been activated.

    Important: If -- -- -- is displayed after pressing the AM-FM button, the customers code has not been entered.

  11. Anytime the ignition is removed and the THEFTLOCK® is activated, the THEFTLOCK® light will flash once every 2 seconds. Anytime the battery power is cycled and the ignition is ON, the display will show LOC. The radio will then need to be unlocked by either the customers code or the factory backup code.

Obtaining the Radio Display Code (Scrambled Backup Code)

Perform the following steps in order to obtain the radio display code:

    Important: In order to display this code, the radio should be in the LOC mode or have SEC displayed before proceeding.

  1. Press and hold the pushbuttons 2 and 3 for approximately 6 seconds until the first 3 digits of the display code are displayed.
  2. Write the numbers down.
  3. Press the AM-FM button. The second 3 digits are displayed.
  4. Write the numbers down.

After approximately 5 seconds or if another button is pressed the display returns to LOC. The display code must be unscrambled in order to acquire the factory backup code that unlocks the radio.

In order to acquire the factory backup code call Delco Electronics Corporation and enter the authorized account number along with the display code that has been written down.

Changing the Customers Code

In order to change the customers code perform the following:

  1. Unlock the radio.
  2. Ensure there is no customer code currently stored in the radio.

In order to determine whether or not there is a customers code stored:

  1. Press and hold the pushbuttons 1 and 4 until the display changes.
  2. If SEC is displayed, there is a customers code stored. Remove the stored code. Refer to Removing the Customers Code. If -- -- -- is displayed there is no code stored and a new code can be added.

Obtaining the Factory Backup Code

If the customers code is unavailable, refer to the Dealer Communications System for the unlock procedures or call Technical Assistance.

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 or TIGHT TAPE-Tight tape
       - E11 or BROKEN TAPE-Broken tape
       - E14 or WRAPPED TAPE-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 or CHECK CD-Optics focus error, maybe due to moisture
       - E21 or CHECK CD-Optics loss of tracking control, maybe due to blemishes on disc
       - E22 or PLAYER ERR-Load/Unload motor problem
       - E23 or PLAYER ERR-Communication problem