CDA-9855R - Sound setting constantly changes

open menu on unit use the home button to turn beep sound on or off;;

what year is your car?newer cars 1999 and up the radio wiring harness goes thru the ecm (electronic control module).if that head unit is not supported it wont work correctly.in a bad case senario the head unit could damage the ecm.

Buy new or call customer support

Your question is lacking some detail , is this a stock radio , after market , and what brand and model . Pictures can help , depending on the siuation code be s radio key is needed or if it's after market do you have a remote ? Try to change stuff with that , could be buttons inop or worst case it's just done. Good luck

Let's do some inexpensive troubleshooting. At the amp switch the rca jacks and see if you still get sound. If you get sound out of the left speaker then the right side output needs to be repaired. But if you get sound out out of the right speaker only then you have a problem with the preout of the stereo and the stereo will need to be repaired. Hope this helps.

when mine does that it is down to the connection of the face to the head unit, push it firmer or remove and replace. it may be that the connection is worn.

i have that same problem. when i turn the volume up, it shuts off but comes back on right away. the only thing i can think of is i'm not running the constant power directly from the positive terminal on the battery (which is what is recommended). not sure if thats the solution but im gonna try and wire it right anyway...

The stereos audio amplifier IC is damaged.

I solved this problem by calling Alpine Electronics customer services.

Yes, I'm sure Alpine will sell you another face but there is still the option of repairing the broken face at a good repair shop. Of course getting a new face is the easiest (read most expensive) way to get you going again.