2012 Prius C Four Aux/Radio Issues

Hey all, I bought a used 2012 Prius C Four recently (complete with the high end audio system, leather heated seats, moonroof, etc. And one of the things I would love to do is run my MP3 player off of the Aux input in the car. However unless I am unable to figure out how to do this through the system I have not been successful at doing this.

I know in the audio system/radio (model 100023) there is a "Source" button on the top right of the screen, however pressing this does nothing. Regardless on how I seem to plug it in or have the player already playing something. I have looked around for other settings or features but nothing seems to get my Aux working.

Speaking of the audio system. I noticed I am unable to use certain features. The Apps button does nothing, going into settings both bluetooth and phone does nothing when pressing on them as well. Is there something wrong with my audio system? Does it need an update and if so how does one apply it? I am just hoping I am missing something here that I have overlooked but I am at a loss as to how to get this simple but desired feature working!

Can anyone enlighten me on this? Thank you in advance!

 

A followup:

I did some digging around on this and after some time and research on the actual head unit itself I noticed the system is composed of two devices, the actual Radio/Interface of the head unit itself and an expansion box that is affixed to the bottom of the unit which handles extra features/functions. I saw that this unit is prone to failure in the long run and that the expansion unit simply ceases to function, losing out on most of the additional features to the radio unit itself. Looking over at the Prius V forums this is mentioned a lot and suggestions of replacement or outright upgrading the head unit for a third party system when this happens. I tried to run Diag on the radio but the diag itself seems to not really provide any kind of information. Finally removing the head unit out to see the model number of the expansion box I was able to find a replacement off ebay for around $90 shipping.

I will be getting the replacement box in on Friday, and I hope to report the results of the replacement soon after. Hopefully this will resolve my issues. The only thing I am uncertain of now is whether or not I should attempt installation with the battery disconnected or not, since the opinions are split down the middle on this and that the battery that will need to be disconnected is not in a typical location. Some guidance on this would be appreciated.

 

Oh boy oh boy, that was sure an interesting Friday.

So the replacement Extension Box came in last Friday, and after work I begin work on the car. Following suggestions I disconnect the battery's negative terminal before proceeding to disconnect the radio. Once the Radio was out I took it back inside to get at the box under the unit. The screws were insanely tight on the unit, I would say they were probably installed with an impact driver with how tight it was. Something I was able to fortunately get loose enough to get them off and replace the old box with the unit I purchased on ebay. The replacement unit itself seems to have come from a 2013 Highlander but was compatible with the 2012 Prius C's radio which should not be that surprising.

20220218_113954 by Faust posted Feb 23, 2022 at 3:34 PM

Once properly replaced and the cables were plugged into their right place I installed the unit back into the car, double checking the cables being plugged in right, hooked up the battery again and when powering on....I get source! I get AUX, I get USB, I get Bluetooth, I get everything that the unit is meant to have. Check on the Apps and Navigation is there, the other apps are all there. Everything is working as intended!

IMG_20220218_210316 by Faust posted Feb 23, 2022 at 3:34 PM

So with that being said and done, the issue is now resolved. If anyone else ends up having a similar issue, chances are they will need a replacement Extension box for their unit. Mine only costs me around 90 with shipping but I see these average around 100-150, still better than having to take it in shop and cost me in the higher 3 or 4 figures. Replacement and Install is relatively simple all things considering, hell for it being my first time working on a Car its easier than some of the laptops I have to take apart at work. Hope this helps others out in the future!