My girlfriend is having a problem with her Honda stereo (I believe the stereo model number is something like 3YC03). She says that on starting up the car last night the stereo volume will not work and Tel Mute flashes on the display.

I assume this is the telephone mute function but the manual does not mention anything regarding it. Failing any help from the manual I have tried the random pushing of buttons and disconnecting the battery but no luck so far.

Any ideas appreciated, if you need further info regarding the stereo please let me know.

 

That's no model number I've ever heard of...

But if the "Tel Mute" icon is flashing, it could be due to improper installation, and the telephone mute wire is uncapped and grounding out behind the radio.

Pull the radio & check it out back there.

 

Ditto the above^^^
I have seen this more then a few times, HUs mute lead gets pinched under HU and metal rear support bracket. 94