I'm starting a thread based off my experience with my 2012 Access Cab. I'm surely not the only one to have experienced this issue, maybe I can help someone find a fix in less time than it took me. This is for the Bluetooth enabled, non jbl, non entune deck with mp3.
Picked up a new access cab in july. Noticed on the drive home that the speakers would pop/scratch an higher, but not excessive volumes. Assumed it was a connectivity issue and didnt mess w it for a few days. Once I dug in I realized that it happened regardless of the source, and it sounded like the amp was clipping.
Took it to the dealer and they diagnosed a blown speaker. When this didn't fix it and after a few more trips to the dealer they flew in a regional tech that specializes in electronics. After some diagnosis his best guess was that the amp was clipping also and told me he'd look into it. He called a few weeks later and said that Panasonic makes the radio for the 2012 access cab and it's different than the radio in the crew cab and the reg cab. It's new from the 2011 and they've already updated it for the 2013 to a different model. He said that Panasonic has acknowledged a clipping issue with the amp at high volumes. It's some sort of high efficiency amp. Since it only affects the access cab 2012 model at higher volumes he said he thinks a recall, or even service bulletin, is unlikely.
So basically if any of you are reading this because you have the same issue, you're screwed. Since the amp in question is internal, the only solution is to replace the radio.
The rest of the post will cover a few of the details and tips regarding the fix/install that ultimately solved the problem, including the tweaks necessary to interface the OEM camera with an aftermarket HU on a 2012.
Axxess ASWC Universal Steering Wheel Control Interface
PAC TR7 Universal Trigger Module
Once I realized I had to go aftermarket and decided on the alpine, the install was pretty straightforward. I purchased the steering wheel interface and trigger module for in motion video. I'm pretty good at distracted driving, but watching video is just stupid. I use it more for the nav setting while rolling aspect. Installing both of these items was pretty easy. Try not to make the mistake I did - read too many forums on here and convince yourself it's difficult. Just follow the directions step by step and you'll have it working in no time.
Decided to add the Alpine KTP-445U amp and run it bridged at 90x2 to the front 6x9 and tweeters. More than enough power, sounds great - and I'm picky. If you buy the amp you'll realize that there is no space behind the dash for mounting. You'll want to extend all the wires, use a 6ft RCA and mount it in the center console. My taco is manual and I'm not sure if it'd be different on an automatic, but there are other threads on here where people have done this.
I'm not biased toward JBL, if anything I'm ignorant toward them but after buying a different brand and having depth issues I settled on the GTO 939's. Holy crap do they sound great on any type of music! I'd recommend them to anyone, but they're hard to find. Went with the JBL tweets because they matched and were well reviewed. I'm happy w them.
If you do install aftermarket speakers here are a few tips. Definitely worth it are the tacotunes.com 6x9 adapter brackets. You'll need something to mount them and the cost/effort of building your own ratio makes sense. I would however advise against buying the hardware kit. I didn't use any of it and it basically amounts to $1.75 in bolts for $9.50. Go to the hardware store and buy what you like.
Opposite advice for the tweeter brackets though. These are soo easy to build with a piece of scrap wood or even a piece of cardboard (dont use cardboard). Just make sure whatever you use is no wider than a quarter inch, and when you mount it you'll mount it on the back side of the bracket and screw the screws in from the rear. Since most tweets are different widths, it's just so much easier to deal with it on your own rather than have the potential for tacotunes to make a mistake and have to do mail in exchanges.
The last things I'll address are the USB for the aftermarket HU and the OEM Camera interface.
For the USB there is a great thread on how to mod the current 2012 here
I screwed my USB up trying that so I just ordered a USB port from a 2013. It fits in the same spot, cost about $85, and there is a pre wired harness you can buy for the rear of it that connects right to the USB. Here's the harness
Finally the OEM Camera Interface
There is an awesome detailed thread of this here
I followed that thread exactly, so thanks to the poster and commenters over there. The only issue is nobody addresses the different harness on the 2012. You'll use the exact same harness as the other post identifies for the actual camera wiring. Just use any mid grade RCA cable. Like the Rad Shack $8 kind that you can pull apart into one.
The wiring for the reverse trigger wire is where this harness is different than the other post.
The other thread shows a small harness with just a red and yellow wire, and an arrow instructing you to use the red. On the 2012 there are more wires, pictured below. Sorry for the blur.
The harness in question is the one near the top left of the photo. There are two red wires in this harness. If you're wiring your camera to the reverse input and want it to function only when you shift into reverse, use the red wire on the back side of the harness. This is the designed operation.
If you're running it to an AUX input and want to camera to constantly run, use the red wire on the front side of the harness. Note that I don't know if the camera running constantly would damage anything so you're on your own there. It is cool for checking out hotties behind you though.
The finished product
That's all! Hopefully this helps someone, let me know if you have any questions or if I left out any details!