Hello all, I just purchased a 2006 SC430 with 124,600 miles on it. I live in Canada, but the car was initially a U.S. car.
Please forgive me if this post in the wrong section. I have been searching the forum to try to find a fix for my "no volume" ML stereo, but have not found an answer to my situation.
When I bought the car the stereo was working fine. Once I got it home I started detailing the inside and then when I wanted to go for a drive the stereo had no volume. So, here's whats happening:
- Volume goes up and down fine, both from dial and steering wheel.
- Voice guidance from Nav works fine.
- All functions, AM, FM, CD and Tape work fine.
- All settings, bass, treble, fader, balance adjust just fine.
- Antenne goes to full length with AM, down a bit when in FM, retracts completely when on CD or Tape.
- When I adjust the volume with the steering wheel controls I am able to press "set" and hear an audible beep.
- All lights work on Nav, Head Unit and climate control console.
I have done a Service Check and System check and here are the pics:





To me it appears my Amp is functioning as well as everything else.
Can anyone shed some light on this situation? Did I inadvertently press some combination of buttons while detailing that would cause this?
Please help, and thank you in advance.

 

Can you tell us more?

Specifically, do you ever hear any music?

Did you say, you hear the car talking to you when you are using the Nav?

When you detailed it, did you do the trunk? Did you shampoo the carpet? Did you pull out any of the modules (radio, A/C Controls, Nav Screen) to get the gunk out of the cracks?

 

If you're in Toronto/Markham area, I can take a quick look at it for ya.

 

I'm going through something similar. But mine is intermittent.
I have everything working except both doors midrange and tweeters. I have been chasing it for two weeks now. My rear seat, drivers side door and most of the trunk is removed.
I have all manuals. I know exactly where the plugs are at and have inspected each one by disconnecting and reconnecting.
Like I said, its intermittent.
I have removed my entire center console inspecting every cable bundle. I did find a pinch in the bundle going down the drivers side door and repaired and replaced the wires and electrical tape.
I changed out the amp with one from an 2006 model but I still have the exact same issue.
I checked the telephone circuit. I dont have one to mute the stereo during an incoming call.
Why cant I trace it out? Because the color codes on the schematics are wrong. The hookup between the NAV system to the stereo is different. So, next is a fox and hound. But it is an incredible pain.

Paul

 

Hi guys, thanks for responding.
DshngDaryl - I never hear any sound, including any hissing or popping noises, except when the Nav talks to me or I press the voice command button on the steering wheel. The sound from the Nav is coming out of the driver's side speakers as it should and the words are clearly audible and it answers me back as well (so mic is working). When I detailed the car I did not remove any modules just a vacuum, dash, wood and leather clean and polish. I remember that I had touched the Audio on/off button on the HU as I was detailing and heard sound for a second, but then I held the **** in to clean it and the HU turned off. When I was done I turned the HU back on and have never heard another sound out of it. Everything works as it should, just no sound - except Nav. Is there another kind of reset? I was going to disconnect the battery and try that, but I'm not a huge proponent of doing that unless really needed. I have not opened up the trunk to look at the amp yet, but the Service Check seems to tell me that things are communicating.

khuong - I live in Kingston so about 2.5 hours away from you. Thank you for the offer.

Raven01750 - It seems we are both having troubles but I have no sound whatsoever - except from the Nav.

 

Well, weirdness sometimes cannot be diagnosed easily. You really should reset everything by disconnecting your battery.
My NAV also seems to be intermmit too. I'm having a great time. 🙁

Paul

 

Ontario, did you try the CD or cassette? I think somehow you muted the sound. I’ll look into my manual .

 

Yes, CD and Tape work perfectly, just no sound. I have put a CD in it and it shows it's playing and I can skip to another track etc., same with the cassette tape. That's what I was wondering, that perhaps I somehow pressed the right combination of buttons to mute the sound because all the HU functions work correctly and everything seems to be communicating. Just no darn sound!!!

Thank you for checking your manual, I appreciate the help.

 

Based on this statement, I think it is your Amplifier. It is not uncommon for them to go bad. It seems like a weird coincidence, but these things can and do happen.

I would check your audio fuses
https://www.autogenius.info/lexus-sc...e-box-diagram/

I would also take the carpet out of the trunk and put your hand on the amplifier.

If it is hot, it is most likely getting power

 

Ontario,
I read the manual. There is no mute function. The only suggestion I can think of is :
- check the steering column volume control and set function
​​​​​​- check the ALS function. It’s your tone button. Push the button 5 times to activate the ALS.
If that doesn’t solve your problem, consider the bad amp as Daryl suggested.

 

Hi DshngDaryl, yes I checked all the fuses, and as I said, everything powers up and functions fine, just no sound. Unless there is an inline or internal fuse near or in the amp I'm not aware of. I will disconnect the battery and try that as a system reset before I dig deeper in the trunk. I know the amps are a common source of trouble, but I'm hoping I don't need to buy a refurbished one because how long will that one last? It seems like your throwing good money after bad.

 

Thanks for checking GmanSC. So, should ALS be "off" or "on"? I assume off. I think already tried that, but will check again.

 

Based on an older model (my 2002) so I could be mistaken, but I don't see the amp as the problem. This is based on hearing nav outputs. That means at least one channel of the amp is good and so there should be music/noise coming from the radio on at least that set of speakers.

Based on absolutely no knowledge, I would guess something in the audio output section of the radio has gone bad. Not sure if wiring can impact given some output. Some part of my brain blocks fully understanding wiring diagrams.

 

I hate to disagree here but according to the electrical schematics, the sound from the NAV comes directly from the NAV ECU at AUO+ and AUO- and does not go through the amp.

Paul

 

Okay, so don't take offense but I have to ask a very simplistic question. Have you tried turning the volume **** up a bunch? The reason I ask is that lots of folks (including me) would use the volume preset button on the steering wheel as as a mute. Turn the volume all the way down and then set that level as the preset. If that was the case and you accidentally bumped that button, then the volume is turned way down. It takes a long time to raise it with the volume up button on the steering wheel and a fair amount of turning on the ****.