Radio type that requires a code on changing batteries? Or when this functionality implemented?

I just recently swapped out car battery in my 2006 Suzuki Forenza, and learned in another thread that the radio may reset and require a code to activate it in such cases. I left the car w/o battery installed at least over a day before I put new one in. So I’d imagine the radio would have reset by then.

However, when I started up car with new battery, radio did not require any code, it just worked.

So I’m wondering:

  • are not all (recent) cars (rather most but not all) programmed with that reset functionality? And I got lucky to be one of those?

  • is the reset code feature only for removable radios? The small rectangular ones that look like you can buy at automotive audio shop (or section of electronics store), which can be swapped for another model/brand, etc.? Or does it also apply to the radio types that look like they’re custom integrated to the car? Because mine was that type, a larger square with build in CD player mounted into the dash, it didn’t really look removable as a swappable component, looked more integrated to me.

  • is this reset feature only started in certain model year of cars like OBDII is only in cars since 1996, etc.?

There really is no rhyme or reason as to which vehicles need to have a radio code to reset their radios. I have owned several cars and trucks from 2000 on and none of them needed a code to reset the radio. I know this since I usually always get a new battery when I acquire a vehicle. So far…so good. The vehicles that I have owned have been Chevy, Ford, Jeep, Dodge and a Volvo for a few days. The Volvo’s battery had just been changed right before I got it so I have no idea if it needed a code or not.

The only car I’ve seen with the battery-reset feature for the radio is my 2000 Honda. I don’t know why since the radio/cd player is pretty crappy.

It was just in response to radios being stolen from cars. It makes them unusable when stolen. Just like locking wheel covers came about because people were stealing them and the locking steering wheels the same way. Now we’ve got Onstar and others that can just disable or locate the car. There are no requirements-its just up to the manufacturer.

Thanks for the insight. And I assume that is up to the radio manufacturer, or is it the car manufacturer?

It varies by car. My old 2005 Acura MDX had a code. My current 2014 Lexus GS doesn’t.

I got in the habit of clipping the clamps of a small battery charger onto the battery cable clamps before I took the battery out of the car, and just left them there until I had a new battery installed. That way there was no interruption in current availability, so the radio didn’t lose its settings, the clock wasn’t reset, the computers on board were happy.

It’s simple enough to do and it made life a bit easier.

Most parts stores sell a memory saver that uses a 9vdc battery or plugs into a jump starter. In addition to the radio codes it also holds the computer codes. I have not used these but have been pretty lucky, only one car I had did not hold the radio presets. Have not had any problems with the radio security feature.

For most cars now its just a good practice to put a battery memory maintainer on it when you disconnect the battery. Just as much to hold the ECM settings as the radio codes. They’re only about $10 but you need to use a new 9V battery each time and don’t tarry for hours doing it.

@SteveCBT I have one of those, the 40" cord is a killer, thinking at first just plug it into another car. I took an old 12v dc power supply for a computer or monitor, got a female power socket, put spade clips on the power supply wires, positive to center of course.

Wonder how many people don’t read the directions and just plug it in their car!

The idea is to make the radio useless to thieves, reducing theft.
But since the thief doesn’t know it needs a code until after he’s stolen it, to me it’s pointless.

I don’t know which ones do it and which ones don’t. But we seem to get the complaint about the radio not working after the battery gets replaced from VW owners quite a bit here. I presume it is b/c of this anti-theft feature, and all they have to do is go to VW to figure out the code to re-initialize the radio.

@“the same mountainbike” well, at least you deny the thief the spoils of his crime. I had a car stereo stolen many years ago. . . when I went to buy a replacement, the installer told me that, based on the condition of the shredded wiring hanging out of my dashboard, it was likely the thief had made the radio unusable (shredded the wiring) in the process of ripping it out of my dash. Somehow that made me feel just a little bit better.

Besides the radio, there are some cars that react badly to the interruption of power. At the least you lose the “learning” that the PCM has stored on how to best manage the engine’s fuel mixture and the transmission’s shifts, so the car may run and drive weird for a while after a battery swap. Some cars have auto up/down power windows that may need to go through a simple reprogramming procedure to learn their stopping points or they may not work. And of course you may lose your radio presets, any customizations, and have to reset your clock.

And worst case scenario, there are some poorly-designed systems that may even require replacing an electronics module or being reprogrammed by a dealer after total power loss.

IMHO every vehicle should be able to recover from a power loss gracefully, but some do so better than others.

Here is an article I found listing some problems after battery replacement: