Sony CDX-51RF 10-disc CD Changer

I’m posting this in case anyone runs into the problem I had with my car’s CD changer.

I got an E-99 error on my remote. I had to reset the RF modulator.

The reset button is accessed through a hole in the side of the modulator unit, which will probably be under your dashboard somewhere.

Simple, really. If you know what to do. Also, it’s a lot easier if you find the hole and reset it that way instead of pulling the cover off the thing before realizing you can get at the button without opening it up.

Hey, it was dark out (not to mention about 19 degrees and windy) and I was working with a flashlight in the driveway.


  1. I am having a similar problem, no output from the player, I am getting an E04 code Could anyone plese help.

  2. Re: Sony Compact Disc Changer System CDX-51RF My remote is broken and works erratically. I’d like to replace it or fix it. But of course, it would cost more than buying a new one. Any suggestions?

  3. Don: I don’t know what the problem with your remote is, but I had a lot of trouble with the track/disc +/- switch on mine after a while. In case it helps out, here’s my little story. Turns out that the plastic ‘handle’ cap wasn’t staying tight on the switch post. I just removed the plastic cap and use the post now. If you’re having trouble with that, give it a try. Otherwise, who knows?

  4. Don, you want a suggestion? buy an alpine or a pioneer next time. sony has gone to crap and rockford is right behind it. that’s just my 2 cents

  5. I’m having the same problem with my sony CDX-52. Keep getting this E-99 error. Any advice besides reseting the modulator. ??

  6. I’ve tried the RB modulator switch, and sometimes it works but other times it doesnt. I am still having problems with mine, sometimes if i disconnect the power to the changer for a long period of time i can plug it back in and it will work, but other times it doesnt cooperate, so I’m baffled. It seems to happen every time i take the cd magazine out.

  7. I have a slightly different problem, ham-fisted… I managed to pull the cable out of the changer remote control. I need a wiring diagram to re-solder it back on. There are 7 very small cables need attaching back onto a terminal block with no markings, anybody have the info please?

  8. I have a Sony CDX-52, and it rarely functions. I turn it on and press play and it shuts off immediately, then fluctuates between on and off. Any suggestions?

  9. please advise i have a cdx -51 in the boot and a sony head unit telling me to reset. i have read your advise and wanted to know what the modulator is ? I am going to have a closer look this evening and take the head unit out so hopefully will answer my own question regards Simon

  10. yo yo i am having similar troubles with my sony cdx-51 changer,i connected everything from antenna adapters and power and ground but still no you are aware these rf modulated type changers have to be tuned in to a certain station, i still have no sound,what to do ?

  11. I am having a similar problem, no output from the player, I am getting an E04 code Could anyone please help my. I have no book about the CDX-51 compact disc changer