I have the same Sony head unit - installed it last fall. It was pretty tight fit - not much room at the back of the unit but I did get it in there. Everything worked fine for a couple drives and then I put the car away for winter. 90 day warranty is up now. Now I have a problem where the head unit will on occasion say "output error" and I have no sound. It seems like it happens when the car is warm. I don't know anything about electronics so I'm at a total loss on how to deal with this. I'd say it works about 40% of the time and almost always if the car is cold and hasn't been sitting in the sun. If the car sits out in the sun but hasn't been driven for hours and the engine is cold, the radio still may not work. Sounds great when it is working. I did wire it to the battery with a fuse and I did maintain the huge Sony fuse box as well. The unit always has power and is lit up - just says output error for all sources when it happens. Any ideas?

 

Not much help from the manual but double check your wirings, speaker connections as well.

 

Maybe, a heat sensing device in the back of the unit? May need to clean a bit more room, for air flow?

 

Ha! Looks like Microsoft wrote the error messages. "Output" error, but it's an "internal" malfunction.

Airflow has always been a problem in the S, compounded by the heat off the transmission tunnel which gets trapped in the radio console area. The other possibility for an intermittent problem is that a wire is pinched through the insulation and expansion/contraction causes it to short to the chassis. I usually try to tuck the wiring under the HU rather than behind it, but it's not easy.

 

There is a "TEMP CAUTION" error message as well so it's probably not temperature related.

 

I would've guessed cold solder joint but if it works better when it's NOT hot that confuses me a little bit.

 

I'll put my money on a bad speaker. Are you running factory speakers or aftermarket 2 way system?

 

I have some Polk speakers front and I installed a set in the rear as well. It's a strange problem...turned car on this morning and radio came on for 1 second then "output error". Driving to work I shut it off and turned it back on and after doing that about 5 times, the radio came back on and worked fine for the rest of the drive. Probably when I go out for lunch it will say output error again. Seems to work better when it's cool outside and the car is cool, but that is not always the case. Without the radio I can hear the rattles and the back of the seat squeaking against the back panel which is not a pleasing sound.

 

This sounds like a bad connection, somewhere. Maybe a grounding point or female-male multi-wire plugs. Good luck!

 

i've seen many reviews saying this sony mex-xb100bt is not a reliable head unit
check the reviews here