Entertainment System: Other Cadillac STS I

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Identifying Concerns

1. In order to isolate the source of the noise/poor reception, identify the ignition switch position that the concern is most noticeable: Turn the ignition switch to the accessory position. Turn ON the radio. Seek up 88-108 FM then 550-1600 AM. Record the number of valid radio stations where the tuner stops. Repeat these steps with the ignition ON, and the engine OFF then again with the engine running.
2. Return the ignition switch to the position that the concern was most noticeable.
3. Remove fuses or circuit breakers one at a time until the noise has been eliminated.
4. Identify what systems or components are powered by the fuse.
5. Reinstall all fuses and circuit breakers.
6. Disconnect the components powered by the fuse one at a time until the concern has been eliminated.

Corrective Action

1. Inspect the ground integrity of the component or system causing the noise.
2. Malfunctioning and marginal components such as relays and solenoids may cause noise and/or poor reception.
3. Always use a braided ground strap when applying additional grounds and keep the ground strap as short as possible.
4. If the noise source is found to be coming from the vehicle harness: Route the antenna cable separately from the wire harness that is emitting the noise. Use aluminum or nickel tape in order to shield the antenna cable. Attempt variations of the following repairs: Add only aluminum or nickel tape before adding a ground strap to the tape. Wrap a ground strap 360 degrees around the tape, securing the other end of the strap to chassis ground.
5. Capacitors work best on switch pops and low frequency noise.
6. Filters work best on high frequency whines and static.
7. After adding any suppression device, inspect all of the vehicle systems for proper operation and function.
8. Whenever possible, make a test harness that includes filters or capacitors. Always inspect the effectiveness and operation before permanent installation.
9. If an audible pop is caused due to operating a switch, perform the following repairs as necessary: Add a capacitor across the contacts of the switch. Add a capacitor from the battery positive voltage (B+) side of the switch to chassis ground. Add a capacitor from the ground side of the switch to chassis ground.
10. Use the following available noise suppression devices: 220 micro farad (50 V) capacitor GM P/N 1227895-Works well for ignition system related noise. 0.47 micro farad capacitor GM P/N 1227894-Works well for switches and relays. Feed through capacitor GM P/N 477371-Works well for high current situations. Filter package GM P/N 1224205-Works well for low current situations. Fuel pump suppressor GM P/N 25027405 53.34 cm (21 in) braided ground strap GM P/N 8910791 48.26 cm (19 in) braided ground strap GM P/N 6286800 26.67 cm (10.5 in) braided ground strap GM P/N 6287160 21.59 cm (8.5 in) braided ground strap GM P/N 12091511

Generator Whine Concerns

1. Inspect the ground terminal and cable for high resistance.
2. Inspect the generator and brackets for loose or coated mounting bolts.
3. Inspect that the ground straps between the engine and the frame are clean and tight.
4. If the noise is still present, inspect the charging system for proper operation.
5. Install a filter GM P/N 1224205 in the battery voltage feed circuit to the radio.
6. If the noise is not eliminated, install the filter in each following variation: Install the filter with the single wire side toward the radio and the ground wire attached to chassis ground. Remove the ground to the filter. Reverse the filter so the 2-wire side is toward the radio with the ground wire attached to chassis ground. Remove the ground from the filter.
7. If the filter GM P/N 1224205 causes a delay when turning the radio ON or OFF, or other problems, remove the filter and install a 0.47 micro farad capacitor to chassis ground.
8. Before reassembling the vehicle, remove any unneeded filters.
9. Test the functionality all of the vehicle systems for proper operation and function.

Radio Poor Reception

Schematic Reference: Radio/Audio System Schematics

Diversity Antenna System

This diversity antenna system is comprised of 3 antenna grid patterns interfacing with the rear defog grid, a radio antenna module, a coax, and a 14-volt power feed from the radio to the antenna module.

In AM and WX mode, the system functions as follows

The antenna module takes the signal from only the AM/FM1 antenna pattern on the rear window. The antenna module amplifies this signal and sends it to the radio. In this mode the radio does not supply any voltage to the center conductor of the coax and there is no feedback signal present on the coax.

In FM mode the system functions as follows

The antenna module takes the best signal from 1 of the 3 FM antenna patterns on the rear window. The antenna module amplifies this signal and sends it to the radio. In this mode, the radio supplies 12 volts to the center conductor of the coax and this switches the module into FM mode. The radio also supplies a feedback signal, along the coax, to the AM/FM antenna module, which indicates the quality of the signal. Based on the measured input signal level and the feedback from the radio, the antenna module switches between the 3 antennas to find the best signal.

The following information lists the most probable cause of the concern to the least probable cause, followed by the appropriate test for that condition. If the test leads to the replacement of a component, always inspect for a poor connection before proceeding with the replacement. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Perform the Antenna System Test and test the antenna coax cable prior to performing any of the following tests.

Poor Reception on Both AM and FM Bands

1. The radio antenna module is not grounded properly. The module grounding screws should be clean and tight. The antenna module ground is either a chassis ground or a ground strap. Measure the resistance from the antenna module base plate to a good ground. Resistance should be 0.20 ohms or less. Find and correct the condition if the resistance is out of specification.
2. The antenna 14-volt switch supply voltage circuit to the radio antenna module is open or shorted to ground. Test the antenna 14-volt switch supply voltage circuit for an open or short to ground. Refer to «Circuit Testing»(ref-197533-S09080459212005101200000) and «Wiring Repairs»(ref-197533-S00106490252005101200000) in Wiring Systems.
3. Defective antenna module-Replace the antenna module. Refer to «Antenna Module Replacement»(ref-197539-S24164926872005101200000) for service procedure.
4. Defective antenna grid-Refer to «Rear Window Replacement»(ref-197534-S16996412062005101200000) in Stationary Windows.

Poor Reception on AM Band Only

1. The antenna 14-volt switch supply voltage circuit to the radio antenna module is open or shorted to ground. Test the antenna 14-volt switch supply voltage circuit for an open or short to ground. Refer to «Circuit Testing»(ref-197533-S09080459212005101200000) and «Wiring Repairs»(ref-197533-S00106490252005101200000) in Wiring Systems.
2. Defective antenna module-Replace the antenna module. Refer to «Antenna Module Replacement»(ref-197539-S24164926872005101200000) for service procedure.
3. Defective antenna grid-Refer to «Rear Window Replacement»(ref-197534-S16996412062005101200000) in Stationary Windows.

Poor Reception on FM Band Only

1. The Antenna 14-volt switch supply voltage circuit to the radio antenna module is open or shorted to ground. Test the antenna 14-volt switch supply voltage circuit for an open or short to ground. Refer to «Circuit Testing»(ref-197533-S09080459212005101200000) and «Wiring Repairs»(ref-197533-S00106490252005101200000) in Wiring Systems.
2. Defective antenna module-Replace the antenna module. Refer to «Antenna Module Replacement»(ref-197539-S24164926872005101200000) for service procedure.
3. Defective antenna grid-Refer to «Rear Window Replacement»(ref-197534-S16996412062005101200000) in Stationary Windows.

Digital Radio Poor or No Reception

Digital Radio Poor or No Reception

Audio Distortion - One or More Speakers

Schematic Reference: Radio/Audio System Schematics

Connector End View Reference: Entertainment Connector End Views

Left Channel - Audio Distortion

Left Front Low Level Audio Signal circuit open - Test the left front low level audio signal circuits for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Right Channel - Audio Distortion

Right Front Low Level Audio Signal circuit open - Test the right front low level audio signal circuits for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

One Speaker - Audio Distortion

1. Speaker output from Amplifier open or shorted to voltage - Test the appropriate speaker output for an open or short to voltage. Refer to «Circuit Testing»(ref-197533-S09080459212005101200000) and «Wiring Repairs»(ref-197533-S00106490252005101200000) in Wiring Systems.
2. Defective speaker - Replace the appropriate speaker. Refer to «Speaker Replacement Reference»(ref-197539-S42067641402005101200000) .
3. Defective Amplifier - Replace the Amplifier. Refer to «Control Module References»(ref-197535-S32949592342005101200000) in Computer/Integrating Systems for Replacement, Setup or Programming.

Audio Distortion from Rear Speaker During 5.1 DSS DVD Playback

Audio output from radio open - Test the appropriate output from the radio for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Steering Wheel Controls Inoperative

Steering Wheel Controls Inoperative

Reduced Volume - One or More Speakers

Schematic Reference: Radio/Audio System Schematics

Connector End View Reference: Entertainment Connector End Views

Left or Right Side - Reduced Volume

1. Front Low Level Audio Signal shorted - Test the Left or Right Front Low Level Audio Signal for a short to ground or to voltage. Refer to audio Wiring Systems.
2. Defective Radio - Replace the Radio. Refer to in Computer/Integrating Systems for Replacement, Setup and Programming.
3. Defective Amplifier - Replace the Amplifier. Refer to in Computer/Integrating Systems for Replacement, Setup and Programming.

Reduced Volume During 5.1 Digital Surround Sound Enabled DVD

1. Front Low Level Audio Signal shorted - Test the Left or Right Front Low Level Audio Signal for a short to ground or to voltage. Refer to audio Wiring Systems.
2. Rear Low Level Audio Signal shorted - Test the Left or Right Rear Low Level Audio Signal for a short to ground or to voltage. Refer to audio Wiring Systems.
3. Center Channel Low Level Audio Signal shorted - Test the Center Channel Low Level Audio Signal for a short to ground or to voltage. Refer to audio Wiring Systems.
4. Subwoofer Low Level Audio Signal shorted - Test the Subwoofer Low Level Audio Signal for a short to ground or to voltage. Refer to audio Wiring Systems.
5. Defective Radio - Replace the Radio. Refer to in Computer/Integrating Systems for Replacement, Setup and Programming.
6. Defective Amplifier - Replace the Amplifier. Refer to in Computer/Integrating Systems for Replacement, Setup and Programming.

Speakers Inoperative - One or More

Schematic Reference: Radio/Audio System Schematics

Connector End View Reference: Entertainment Connector End Views

All Seat Speakers Inoperative

Seat speaker outputs from Amplifier shorted - Test the seat speaker outputs for a short to ground or to voltage. Refer to and in Wiring Systems.

Left and Right I/P Speakers Inoperative

Front speaker outputs from the Amplifier shorted - Test the Left and Right Front Speaker Output circuits for a short to ground or to voltage. Refer to and in Wiring Systems.

All Speakers on One Channel Inoperative Only on Digital Radio

1. Right or left audio signal circuit open or shorted-Test all audio signal circuits for an open or short. Refer to and in Wiring Systems.
2. No audio output from the digital radio receiver-Replace the digital radio receiver. Refer to in Computer/Integrating Systems.

One Speaker Inoperative

1. Speaker output open or shorted-Test the appropriate speaker output circuits for an open or short. Refer to and in Wiring Systems.
2. No audio output from the amplifier-Test for any AC voltage between the appropriate speaker output circuits at the speaker harness connector, disconnected with the radio volume adjusted to an audible level. If AC voltage is present, replace the speaker. If no AC voltage is present, replace the amplifier. Refer to in Computer/Integrating Systems.
3. Defective speaker-Replace the inoperative speaker.

Speakers Inoperative - All

Schematic Reference: Radio/Audio System Schematics

Connector End View Reference: Entertainment Connector End Views

All Speakers Inoperative Only on Digital Radio

1. Right or left audio signal circuit shorted to battery positive voltage-Test all audio signal circuits for a short to battery positive voltage. Refer to «Circuit Testing»(ref-197533-S09080459212005101200000) and «Wiring Repairs»(ref-197533-S00106490252005101200000) in Wiring Systems.
2. No audio output from the digital radio receiver-Replace the digital radio receiver. Refer to «Control Module References»(ref-197535-S32949592342005101200000) .

Radio Theft Procedure

Complete the following procedure, using a scan tool, in order to properly set up communication

1. At the Main Menu screen, select Diagnostics.
2. At the Vehicle Identification screen, select the following options: Model Year Passenger Car
3. At the Vehicle Identification screen, select the appropriate model.
4. At the System Selection Menu screen, select Body and Accessories.
5. At the Body Screen, select Entertainment.
6. At the Entertainment screen, select Module Replacement/Setup.
7. At the Module Replacement/Setup screen, select Radio.
8. At the Radio screen select VIN Relearn
9. Select the appropriate radio type.
10. Follow the on screen instructions.
11. Press EXIT on the scan tool and cycle the ignition.

Digital Radio Receiver Setup

For the digital radio receiver, complete the following procedure with the key in the ON position. Use a scan tool in order to properly set up communication

1. At the Main Menu screen, select Diagnostics.
2. At the Vehicle Identification screen, select the following options: Model Year Vehicle Line
3. At the System Selection Menu screen, select Body.
4. At the Vehicle Identification screen, select the following: Platform Type Body Type
5. At the Body screen, select Digital Radio Receiver.
6. Select Special Functions.
7. At the Special Functions screen, select DRR Setup.

XM Activation

1. Turn the radio on, tune to the XM channel 0, and record the Radio ID. The Radio ID will be needed for activation of the new receiver.
2. Call XM Radio at 1-800-556-3600 to deactivate the faulty receiver and activate the new receiver.
3. Park the vehicle outside in an area with an unobstructed view of the southern sky.
4. Leave the vehicle outside with the ignition switch in the Run position and the radio on for 20 minutes to activate XM service.
5. Once activated the radio will receive the remaining XM Radio channels.

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

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

AM Reception

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

1. Bend around Obstacles
2. Follow the curvature of the earth
3. 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 miles).

FM Reception

The shorter wavelengths of the higher frequency FM band

1. Reflect off obstacles
2. Are absorbed by the ground
3. Penetrate the ionosphere

Broadcasts in the FM band are limited to "line of sight" reception which is typically 40 km (25 miles). 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

1. Height of the broadcast antenna
2. Height of the receiving antenna
3. 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 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.

This vehicle has a scanning diversity AM/FM antenna system. This system consists of the following parts

1. 3 Antenna Grid Patterns on the rear window interfacing with the rear defog grid.
2. AM/FM Antenna Module
3. Coax - The radio sends a 12 volt signal to module when in FM mode (less than 1 volt in AM and WX mode). The radio also sends feedback on signal quality to module in FM mode.
4. 12V power feed from the Radio to the Antenna Module 0.35 pink wire with single pin connector. The 12V power feed from the radio to the AM/FM antenna module is on any time the radio is on.
5. Radio

In AM and WX mode the system functions as follows

The AM/FM antenna module takes the signal from only the AM/FM1 antenna pattern on the rear window. The AM/FM antenna module amplifies this signal and sends it to the radio. In this mode the radio does not supply any voltage to the center conductor of the coax and there is no feedback signal present on the coax.

In FM mode the system functions as follows

The AM/FM antenna module takes the best signal from one of the three (3) FM antenna patterns on the rear window. The AM/FM antenna module amplifies this signal and sends it to the radio. In this mode the radio supplies 12V to the center conductor of the coax and this switches the module into FM mode. The radio also supplies a feedback signal, along the coax, to the AM/FM antenna module, which indicates the quality of the signal. Based on measured input signal level and the feedback from the radio the AM/FM antenna module switches between the 3 antennas to find the best signal.

Audio Amplifier

The radio or digital radio receiver (routed through the radio), and Onstar® supplies low level audio signals to the audio amplifier in order to boost the signal sent to the speakers.

The radio uses the antenna input signal to create a stereo audio output signal, which is sent at the user-defined volume level to the audio amplifier. The audio amplifier amplifies the signal and sends it to the appropriate speakers. Tone, balance and fade information is sent by the radio to the audio amplifier via the GMLAN communication circuit. Additional output processing is provided by the noise-canceling microphone. The microphone monitors interior ambient noise allowing the audio amplifier to modify the audio output. This maintains the sound at an enjoyable level.

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 GMLAN 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 the instrument panel module (IPM) on the GMLAN circuit. 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. The IPM 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 GMLAN 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 the instrument panel module (IPM) on the GMLAN circuit. If a mis-match occurs, the radio display will indicate to the user the digital radio receiver is locked. This will occur if a digital radio receiver is installed from another vehicle. The digital radio receiver cannot be unlocked, it must be replaced.

Radio Personalization w/Home and Away Feature (If equipped)

This feature allows 2 different drivers to store and recall specific radio settings. The settings recalled by the radio are determined by which remote keyless entry (RKE) transmitter (1 or 2) is used to enter the vehicle. The number on the back of the RKE transmitter corresponds to driver 1 or driver 2. The radio settings automatically adjust to where they were last set by the identified driver. The settings can also be recalled by briefly pressing the MEMORY seat button 1 or button 2 located on the drivers door.

The radio can store home and away presets. Home and away presets allow you to use 1 set of preset radio settings in the area where you live, and another set when you go out of town. That way, you do not need to reprogram your presets every time you travel. With the radio off and the clock displayed, use FF and RW to select home or away presets. In order to select the away presets, press and hold FF for 5 counts until you hear a beep. The next time the radio comes on, the away presets are active. In order to select the home presets, press and hold RW for 5 counts until you hear a beep. The next time the radio comes on, the home presets are active.

When battery power is removed and later applied, you do not have to reset your home radio presets because the radio remembers the presets. However, you do have to reset the away radio presets.

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

1. RDS functions are provided in the FM broadcast band only.
2. RDS functions will only work with FM broadcast stations that are broadcasting RDS data.
3. Not all FM Broadcast stations broadcast RDS data or offer all of the RDS services.
4. 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

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

Finding an RDS Station

To find an RDS station press the RDS button. The radio will seek to the next RDS station.

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 TA 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 TA 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, TA 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 STATION FOUND.

Viewing Messages

When MSG 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 MSG 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 MSG button again.

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 broadcast once a minute. To set the clock press the RDS SELECT button. Then press and hold either the HR or MN button. If the broadcaster is sending clock time data the display should show STATION TIME IS xx:xx. If the time is acceptable, simply continue to press and hold the HR or MN button until the display shows TIME UPDATED.

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 instrument panel module (IPM). This results in a generated voltage, unique to the particular button. The IPM alerts the radio via GMLAN message that the button has been pressed, and the radio responds, just as if the corresponding radio front panel button had been pressed.

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.

The radio controls communicate with the digital radio receiver via the GMLAN communication circuit. The digital radio receiver sends low level audio signals to the audio amplifier.

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

Selecting a PTY

The LEVEL + or - buttons can be used to scroll through the list of available program types (PTY). Press the PTY button, followed by the LEVEL + or - buttons to scroll through the available program types. When the desired PTY is shown on the display, press the TUNE/SEEK or SCAN button twice. The radio will seek the next station of that type.

XM Advisory Messages