IMPALA RADIO FAQ
The purpose of this FAQ (Frequently Asked Questions) is to answer some of the questions that I have received concerning the audio system in the Impala. In the past, I have tried to give due credit to contributors. However, this collection is from different sources over a long period and I have lost the original sources. So I'll just say that credit for this FAQ should be given to you, the readers of this site.
Q: I was told that the premium sound system in my Impala includes eight speakers. I can find only 4 speaker grills. Did they forget to install the other four?
Q: Can I replace my speakers?
Q: Can I replace my radio?
Q: Is the OnStar brain in the radio or trunk mounted amplifier?
Q: Can I replace my radio and still retain OnStar?
Q: Can I replace my radio and still configure my car?
Q: How do I reset the Change Engine Oil Message without the factory radio?
Q: How do I reset the Tire Inflation Monitor System without the factory radio?
Q: Why would I relocate my head unit to the trunk?
Q: I want to install an aftermarket head unit but does this mean I have to give up my steering wheel controls?
Q: Can I use a portable CD player adaptor with my cassette tape player radio? (This only applies to cars equipped with the AM/FM cassette factory radio.)
Q: I removed my radio and none of the warning chimes work.
Q: I am installing an aftermarket unit but I cannot locate the ACC (aka ignition) wire?
Q: If I remove my radio, will the dealer have to reactivate it if I want to reinstall it into my car?
Q: Where is the amp?
Q: Why does the amp bypass work?
Q: Why does the rear speakers sound louder/different in a vehicle that is not equipped with the factory amp as opposed to one that does?
Q: What is the story behind the 104 and 103 amp?
Q: If I replace the amp with an aftermarket one, will I need line level converters?
Q: Can I install a CD changer?
Q: I was told that the premium sound system in my Impala includes eight speakers. I can find only 4 speaker grills. Did they forget to install the other four?
A: The front doors contain two speakers each, a main speaker and a tweeter. The rear deck contains coaxial speakers. Normally, this type of speaker is called a 2-way speaker and is considered one speaker. However, to GM, this is two separate speakers (a main and a tweeter) so the Impala is equipped with 4 speakers in the package shelf.
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Q: Can I replace my speakers?
A: Yes. Changing out the speakers should not have a detrimental affect on the system.
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Q: Can I replace my radio?
A: Yes. Contrary to what many dealers and aftermarket installers may say, it is possible to replace the stock factory head unit with an aftermarket one. However, there are other factors that have to be taken into consideration.
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Q: Is the OnStar brain in the radio or trunk mounted amplifier?
A: No. The OnStar hardware is under the black cover in the trunk, mounted on the drivers side rear wheelwell hump. It's about the size of a loaf of bread. The OnStar system consists of the “brain” in the trunk, the cellular antenna on the rear windshield, the GPS antenna under the package shelf, the rear view mirror (contains the controls and the microphone) and the radio (used for the OnStar audio output). The amp is not a part of the system.
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Q: Can I replace my radio and still retain OnStar?
A: Maybe. When OnStar is activated, the OnStar system sends a signal to the radio via the class 2 serial data circuit to mute the audio system and transfer the OnStar audio signal to the radio. So to retain OnStar, you would have to install a separate speaker into your vehicle and connect it to the audio signal output of the OnStar unit. There is a product out there called “Starmod2” that is supposed to interface OnStar with aftermarket head units.
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Q: Can I replace my radio and still configure my car?
A: No. You need the radio to change the convenience features. The exception to this is the Change Engine Oil Message and the Tire Inflation Monitor. Another option is to relocate the factory head unit. See the Accessories page for more information concerning relocation harnesses.
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Q: How do I reset the Change Engine Oil Message without the factory radio?
A: Turn the ignition to ON, with the engine off.
Fully press and release the accelerator pedal three times within five seconds. The Change Engine Oil message will flash, signifying that the message was reset. If it says on, you need to repeat the procedure.
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Q: How do I reset the Tire Inflation Monitor System without the factory radio?
A: Turn the ignition to ON.
Turn the exterior lamp control from OFF to parking lamps three times.
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Q: Why would I relocate my head unit to the trunk?
A: Many of the convenience features can be reset or customized through the radio. Some of these include: oil life monitor, tire pressure monitor, delayed headlamp illumination, auto door lock and unlock. The oil life and tire pressure monitor can be changed without the radio, but the rest cannot. You could just plug the radio back in when you needed to change something, but that involves tearing apart the dash again.
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Q: I want to install an aftermarket head unit but does this mean I have to give up my steering wheel controls?
A: No. PAC has a unit that will interface between the steering wheel controls and an aftermarket head unit that can be controlled with an IR remote. See the Crutchfield link on the Accessories page for more info.
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Q: Can I use a portable CD player adaptor with my cassette tape player radio? (This only applies to cars equipped with the AM/FM cassette factory radio.)
A: Yes, after you activate the bypass feature. (From the Owners Manual)
1) Turn the radio off.
2) Press and hole the TAPE AUX button for five seconds. READY will appear on the display for five seconds, indicating the feature is active.
3) Insert the adapter into the cassette slot. It will power up the radio and begin playing. This override routing will remain active until EJT is pressed.
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Q: I removed my radio and none of the warning chimes work.
A: The radio is the vehicle chime producer. When it receives an audio warning request via the class 2 serial data line, the radio generates the chimes through the left front speaker. Removing the radio will disable vehicle chimes. According to the users manual, you can install a “chime module” to retain the chimes, but I have no idea what that is or how you install one. (2001 Owners Manual, pg 3-46) The service manual describes a Multifunction Alarm Module that is installed in vehicles with RPO UL5 (Radio Delete Option). It would be located behind the radio delete plate. I don't know if this can be used in conjunction with an aftermarket head unit.
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Q: I am installing an aftermarket unit but I cannot locate the ACC (aka ignition) wire?
A: Typically, car radios need two +12 volt sources to operate. One wire is connected to a source that has +12 volts at all times. This is where the radio draws its power to operate. The other source only carries +12 volts when the key is in the ON or ACC position. This signal turns the radio on. This is not how the Impala radio works.
The vehicle monitors the electrical system and sends a signal through the serial data circuit to turn the radio on. It's likely this signal is more than a simple 12-volt signal and you will not be able to use this as the ACC for a new radio.
However, there may be another ACC source. The auxiliary power drop connector has both a battery positive voltage and an accessory voltage. I recommend that you take a multimeter and probe pin C (this is the yellow wire) and see if it is ACC. A pin out diagram can be found in the How To article on the auxiliary power drop connector.
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Q: If I remove my radio, will the dealer have to reactivate it if I want to reinstall it into my car?
A: No. In previous model years, a security code had to be programmed into the radio for the radio to operate. In the Impala, the radio is programmed with a portion of the vehicle's VIN. When the radio is activated, it compares the VIN it has stored with the VIN that is transmitted from a module in the vehicle. If a mismatch occurs, the radio will lock and can only be unlocked with a scan tool. You can remove the radio and reinstall it in the same vehicle with no problems, but you cannot install the radio into a different vehicle unless the dealer reprograms the radio.
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Q: Where is the amp?
A: The amp is installed under the package shelf in the trunk. It is a silver box mounted between the rear speakers.
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Q1: Why does the amp bypass work?
Q2: Why does the rear speakers sound louder/different in a vehicle that is not equipped with the factory amp as opposed to one that does?
A: The amplifier sends an Amplifier Present signal to the radio. The radio sends low-level audio signals to the amp, which in turn amplifies this signal and sends it to the rear speakers. If there is no amplifier, the rear speakers are connected directly to the radio and the radio sends speaker level audio signals.
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Q: What is the story behind the 104 and 103 amp?
A: From the beginning, a number of people were dissatisfied with the sound of the premium sound system. A couple of owners came up with a way to bypass the factory amp and drive the rear speakers directly with the head unit. See the How-To article on the amplifier bypass for more info. Many felt this dramatically improved the sound.
The amplifier part number changed in the 2001 model year, somewhere around 12/00. The old part number is 10432572 and the new part number is 10309548. People who were talking about the amplifiers shortened the part numbers to differentiate between the the amplifiers (104 and 103, respectively). Note: there was an even older part number, 10289187, that reportedly has the same lackluster performance as the 104 amp.
Owners have said that the sound quality of the 103 amp is an improvement over the 104 amp and have pursued replacement through their Chevy dealers. Some have been successful in getting their amps replaced under warranty and are happy with the change.
Others feel that the amps are ok and have replaced the rear speakers with aftermarket ones instead. They say this upgrade really improves the system.
Sound quality is a matter of opinion. Some owners are satisfied with their existing system and see no reason to change it.
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Q: If I replace the amp with an aftermarket one, will I need line level converters?
A: Yes. Without the amplifier present signal, the radio will output speaker level audio signals through the rear speaker harness. This signal will have to be dropped back to line level for the aftermarket amp, unless the amp can accept speaker level audio signals. However, if you can determine what the Amplifier Present signal is and send that to the radio, you may not need the converters.
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Q: Can I install a CD changer?
A: Yes. Well, it depends, actually. One option is to install a FM modulated CD changer. GM carries a FM modulated changer or you can find a nice aftermarket one. If you have the base AM/FM radio, this is your only option. If you have the AM/FM cassette radio, you can install the Remote CD Wiring Harness (Option Code WX9) and use the GM 12 disk changer. If you have the AM/FM CD radio or the AM/FM CD cassette radio the harness is already installed in your vehicle. The harness is installed, but is not connected to the head unit. See the How-To article on the CD Changer for more info. Crutchfield carries an aftermarket CD changer that you can use instead of the GM one. You can find a link to them on the Accessories page.
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