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Advantage Online: 2003 Archives

WORKING WITH ANTI-THEFT RADIOS

September 15, 2003 -Many collision repair procedures require the battery to be disconnected before repairs are started. In the past, disconnecting the battery required recording the radio station presets and the positions for memory seats and steering columns, if the vehicle was so equipped. Once the repairs were completed and the battery reconnected, the presets and memory positions were reentered and the clock was reset. The increased use of electronics on today's vehicles has led to additional considerations when the battery is disconnected on some vehicles. It may be necessary to perform a relearning procedure on the vehicle to avoid driveability problems, and power accessory features may require initialization procedures in order to function properly if the battery was disconnected. This article looks at one of those increasingly complicated features: anti-theft radios.

Before disconnecting the battery, identify whether the radio has an anti-theft feature, and if so, how the feature works. Anti-theft radios may require entering a numeric code after disconnecting the battery or any other procedure that removes power from the radio. The code may have been programmed by the vehicle maker, or chosen and programmed by the vehicle owner. Either way, if the battery is disconnected and the code is not input, the radio will not work. Looking at indicators on the faceplate can identify most, but not all, anti-theft radios. For example, Honda and Acura anti-theft radios have the words "ANTI THEFT" on the faceplate (see Figure 1). General Motors anti-theft radios have the term "THEFTLOCK" on the faceplate (see Figure 2). Other ways of identifying the presence of an anti-theft radio include checking the vehicle owner's manual or the vehicle service manual.

Once it has been determined that the radio has an anti-theft feature, you need to determine how the feature works. The vehicle service manual or owner's manual is the best source of this information. Vehicle makers have used a variety of methods to add anti-theft features to the radios. For example, Honda and Acura vehicles built after 1991 have factory-programmed five digit codes. Audi vehicles built after 1985 also have factory-coded radios with four digit codes until 2002, when "smart coding" was introduced. With this system, the radio and body control module communicate to ensure that the radio is installed in the correct vehicle. If the radio does not receive the correct VIN information from the body control module, it locks up and will not function. The advantage of this system is that a loss of power to the radio will not require a code to be input as long as the radio remains in the original vehicle. General Motors vehicles built after 1994 have one of two different versions of THEFTLOCK®. The first version must be activated by the vehicle owner and has a three or four digit code that is chosen by the person activating the THEFTLOCK® feature. If the THEFTLOCK® feature has been activated, there will be a small blinking red light on the radio face next to the THEFTLOCK® logo. The second version of THEFTLOCK® is similar to Audi "smart coding." The radio and body control module communicate with each other to ensure that the radio is installed in the correct vehicle. Which version of the THEFTLOCK® feature depends on the model and year of the vehicle. For example, the 1994-2000 Pontiac Grand Am uses the coded THEFTLOCK®, and the 2001-2004 Pontiac Grand Am uses the VIN-based THEFTLOCK®. However, the Chevrolet Corvette uses the coded version of THEFTLOCK® from 1994–2004.

Accessing And Entering The Code

If it has been determined that the radio uses an anti-theft feature that requires a code to be entered after the battery is disconnected, the next consideration is accessing the code. Start by asking the vehicle owner if they know the security code for the radio. If not, a little detective work may be in order. Factory-coded radios may have a sticker in the owner's manual or on a radio card in the owner's manual that contains the code. If the code is not known and can't be found, a dealership may have to be contacted for help determining the code. General Motors coded THEFTLOCK® radios have a backup unlocking code that can be accessed by a General Motors dealer or a Delco® radio repair center if the owner programmed security code is not available. Honda, Acura and Audi anti-theft radios are examples that will require radio removal to access the radio serial number that a dealer needs to obtain the factory security code. Sometimes the original dealer for a vehicle may keep records of the radio security code for factory-coded radios.

Once the security code for the radio is known, the correct procedure for entering it must be determined. Vehicle makers have a variety of procedures that are used to unlock the radios. For example, to enter the security code into Honda and Acura anti-theft radios, simply turn the ignition to the ON position and turn the radio ON. The radio display should show CODE if the radio is locked. Using the numbered radio station preset buttons the security code is entered. The code 25364 would be entered by pushing the number "2" preset button followed by the numbers "5," "3," "6" and "4" buttons in that order. The radio display will then change to the display of the radio station frequency that the radio is tuned to and the radio will function.

To unlock a factory Audi Delta radio, you first turn the radio ON. The letters SAFE appear on the display. Push and hold the "AM" button, then without letting up the "AM" button push and hold the "ARI-Z" button. The display should now show "1000." Next, release the "AM" and "ARI-Z" buttons. The code can now be entered using the radio preset station buttons, 1-4. Button one changes the first digit in the code ("1"000), button two changes the second digit in the code (1"0"00), button three the third digit, and button four the last digit in the code. Each preset button is pushed multiple times to step through the digits one through nine to change the display to the correct code. Code "1246" would be entered by pushing button "2" two times, pushing button "3" four times, and pushing button "4" six times. Button "1" is not pushed because the display already shows the correct digit in that position. After entering the correct code, push and hold down the "AM" and "ARI-Z" buttons as before. The display will then show "SAFE" and the two buttons can be released. The radio should now play correctly.

See the video below for a demonstration of how to unlock the anti-theft radio in a 1997 Pontiac Grand Am.

Limited Attempts

Another consideration with anti-theft radios is that there is typically a limit to the number of attempts for entering the security code. If the incorrect code is entered the maximum number of allowable times, the radio will lock up and not allow the code to be entered and may show a new message on the display. General Motors' THEFTLOCK® radios will show

"INOP" on the screen (see Figure 3), Audi Gamma radios will show the number of unsuccessful attempts that were made to reset the radio, and the Audi Delta radio will continue to show "SAFE" on the display but will not move on to the next step for entering the code. The number of attempts allowed before the radio locks up varies from make-to-make. The General Motors THEFTLOCK® radios will lock up after entering a wrong code eight times, but Audi radios only allow three wrong entries before not accepting code entry. Most radios will give you a second chance if you exceeded the maximum number of incorrect entries and know the procedure for activating this second chance feature. The second chance procedure may be simply disconnecting the battery again, or leaving the ignition ON for at least one hour. Both the Audi and General Motors radios will reset after the ignition has been in the ON position for one hour. The Audi radio will give you three more chances to enter the correct code and then may permanently lock up, requiring replacement. The General Motors THEFTLOCK® radio will give you three more chances of eight tries per chance to get the code right before permanently locking up.

Conclusion

Knowing whether or not a vehicle has a security code protected anti-theft radio before disconnecting the battery, or removing power from the radio in any other way, can keep from causing a last minute scramble to make an inoperable radio work before a customer picks up their vehicle. As can be seen, acquiring a security code when the vehicle owner does not know it is something that may not be possible in a limited time frame. Getting this information at the beginning of the repair process will ensure that vehicle delivery is not delayed by an inoperable anti-theft radio. Always understand how an anti-theft radio works and what the correct resetting procedures are before attempting to unlock one to avoid ruining a radio by exceeding the maximum allowable number of code inputs.