How To Get The Most From You Miata Radio's Built-In Security Features

By David DeNuzzo

Greetings fellow Miata Enthusiasts,

This document is intended to help you get the most from your Miata Original Equipment Manufacturer (OEM) radio and understand its built-in security features. The information in this document is correct to the best of my knowledge, and all procedures have been tested on my own 1992 Miata. However, I cannot guarantee the accuracy of these instructions nor warrant the results you may obtain with them.


When the Miata was first introduced in 1989 (as a '90 model), not all cars came equipped with a factory radio. However, as the years went on, more and more Miatas were shipped with a radio, and for several years now, ALL new Miatas have come equipped with a radio. There have been at least three different types of OEM radio head units (the AM/FM tuner) used in the Miata. They are all made by Panasonic. The majority use a black face plate - I'll call these the standard unit. The other two varieties feature a silver/chrome face plate and the Mazda Sensory Sound (MSS) system. One first appeared in the '93 Black & Red LE, and was used elsewhere as well. The newest unit first appeared on the '95 Leather package cars with MSS stereo upgrade. The procedures described here have only been tested on a 1992 "standard" Miata stereo, and not any of the newer MSS systems. They may be the same, or they may not.


The Mazda Miata features an OEM stereo made by Panasonic which has some useful security features, both active and passive. It is important to understand what these features can and cannot do for you, and how you can use them to your advantage.

Some of the passive security features of the OEM radio include:

  1. A non-standard size (1.5 DIN) which will not easily install in many automobiles.
  2. A label on the front which says "Mazda".
  3. A control labeled H.R. SP (Headrest Speakers) which is not found on any other stereo.
  4. A label on the front which says "Anti-Theft System".

These features combine to make the Miata radio a unique thing, and as such, limit the attractive use (though certainly not the only use) of this radio to the Miata. Also, the last item might deter would-be thieves who are put off by the anti-theft wording.

This wording leads us to the primary active security feature of the Miata radio:

A programmable security code which will lock the radio if power is interrupted.

I call this feature active because it requires action from the owner to use the feature. However, from the radio's point of view, it does not take any action to prevent its theft, but rather its use after being stolen. The rest of this discussion is centered primarily around the use of the programmable security code.

Most Miata owners are probably aware of the programmable security code feature of their radios. After all, the radio says "Anti-Theft" right on the front. However, most do not know how to actually use the system, and even those who do have probably not bothered to do so. Some reasons for this are:

1. The programming of the security code can be tricky. It is possible to think you are activating the code, when in fact you are deactivating it. There is no way to know that the code has been set.

2. The security code lock-out is activated whenever the power is cut to the Miata radio. This includes when the car is being worked on and the battery is disconnected, or when the battery goes dead for whatever reason. It is a pain to deal with the security code during these circumstances.

3. The security code lock-out is activated ONLY when the power is cut to the Miata radio. It is not possible to activate the lock-out manually, either by accident or on purpose. This defeats some of the effectiveness of the system, as the radio cannot be locked out for a valet or joy rider.

4. Many owners are afraid that they will forget the code. This fear is made worse by the ominous tone of the Mazda Owner's Manual, which states that when the code is forgotten, "the [radio] unit must be replaced by an Authorized Mazda Dealer at the owner's expense." This is absolutely untrue!

By learning how to use your radio's security code, you can eliminate these problems. You will learn how to set and clear the code easily, and be assured that if you should ever forget the code, the radio is not junk.

But, with all these hassles, why would you want to bother setting the security code? Good question. I'm not sure I can provide a complete answer. Since the security code setting (on or off) is not obvious to would-be thieves, the feature is only useful AFTER the radio has been stolen. Therefore, whether or not you set your security code will not do YOU any good (don't think you'll get your radio back - you won't), but it may discourage the same thief from going after other Miatas. And if more Miata owners code their radios, fewer may get ripped off.

On the other hand, any security system can be defeated by those who know how to do it, and any determined thief will defeat your radio's built-in security system. And while the passive features of the radio limit its attractiveness to the average petty thief, a professional will know that there are ready buyers for stolen Miata radios, coded or not.

Still, I recommend you know how to set and clear your radio's security code, and what to do when all else fails. After that, you'll have to make up your own mind.


Setting and clearing the security code in your Miata radio is not difficult, but there are some points you'll need to be aware of. In the 1992 Miata Owner's Manual, these steps are detailed on pages 4-53 to 4-57. You should be able to find them in a similar part of your own manual.

It is not possible to lock up your radio by setting or clearing the security code, so don't be too alarmed if you make a mistake. Start by turning the Miata's ignition key on to the ACC(1) position, and turn the radio off.

Both the setting and clearing of the security code require the depressing of the REW and FF buttons simultaneously. This brings up the word "code" on the display. Then the REW and FF buttons must be pressed again to bring up "----" on the display.

The four digits of the code are then entered by using the numbers 1, 2, 3, & 4 on the radio station pre-set buttons. Each time you press the "1" button, the first digit increases by one, each time you press the "2" button, the second digit increases by one, etc.

When all four digits of the code have been entered, press and hold the REW and FF buttons simultaneously until a beep is heard. The word "code" will then appear. THIS IS THE IMPORTANT PART! If the word "code" is flashing, then the security code has been set and is ready to be activated when the radio power is interrupted. If the word "code" is NOT flashing, then the security code has been cleared and deactivated. Remember, flashing light equals warning - i.e. security set.

If the security code had been set before you started, and you did not enter the correct code, the radio will display an "Err" message, then shut off. This does not affect the operation of the radio. You may use it as normal, or attempt to clear the security code again.

When the security code has been properly programmed, and the power to the radio is interrupted, the security system activates and prevents the radio from being operated until the proper code is entered. The word "code" flashes constantly in the display. As mentioned before, power interruptions can be caused by disconnecting the battery for service, or by having the battery drain for some reason.

If the security system of your radio is activated, and the word "code" continually flashes in the display, normal operation cannot resume until the security code has been entered into the radio. This is done in the same manner as described above for SETTING the code. The code remains set when the process is completed and the word "code" flashes to indicate success. Remember, flashing light equals warning - i.e. security set.


If the security system of your radio is activated, and the word "code" continually flashes in the display, and you attempt to enter the code but do not get it right, the word "Err" appears. Then the system shuts off and the word "code" begins flashing again. If you make three attempts to enter the code under these circumstances, and do not enter the correct code, the system will shut down completely and display only the word "Err". The radio will not function at all and there is no response to any of the buttons. What to do?

Do not panic! Contrary to what the Miata Owner's Manual says, the radio does NOT need to be replaced. It does not even need to be removed from the car. There is a simple 6-step procedure of button pressing and code entry which will reactivate the radio.

While this procedure is not general knowledge, it is certainly well known in the Miata community. The fact of the matter is that while Mazda may have intended to keep this information private in its own channels, the information has been made public in several ways.

At the time of this writing, the Miata mailing list administrator has decided not to let this information remain as part of the list archives. Therefore, I will not include the radio unlocking instructions here. However, you may see if other members of the mailing list can send you the information in a private communication.

(Editor's Note: The procedure is now published in the General Maintenance section of the FAQ.)

Also, all Mazda dealers should know how to unlock your radio, as well as many Mazda certified service centers. However, every service-writer at every dealership has their own personality and policy. Some may be willing to reset your radio at no charge. It only takes a minute. But I have also heard of Miata owners being charged $600 by a dealer for a new radio when all they needed was a code lock-out cleared. So be warned and be prepared!

I hope you find this information helpful. Good luck and good coding!


David D./Redfire
Sacramento, CA
Red '92B

Back to the FAQ

04 February, 1999