ser67

The sound from the radio has suddenly stopped, Nav sound works fine.

Now nothing comes out, but CD and radio work fine - except no sound.

It started doing it earlier this afternoon, I used the steering wheel 'mode' button and it came back to life - my thought was I'd selected an empty station, so used mode to try another band.

No even this doesnt work.

I've tried the microsoft solution - off/on etc.. - is there a system reset I can try to re-boot everything ?

I've tried searching on this forum, and there is a lot of info, just want to understand what it is, and how I can fix it.

The car went in the other week for some body shop work, and they must have disconnected the battery as the seat settings were all gone, as were all the radio channels.

This is probably what has caused my problem but from what I've read, if you still get noises from the nav, then the amp is fine - but is somehow off.

I've tried the radio off, roof down, roof up to see if this resets it but nothing.

Any help from anyone will be gratefully accepted.

Thanks

Habious

From what I understand, there's a separate amp for the Nav voice...and then the big ML amp for the stereo system.

The ML amp is known for not being very robust.

Unless you're really lucky and it's something like a fuse (unlikely, since you said it stopped working, worked for a little while, then stopped working again), you probably have a dead amp.

Replacing it can be a pain. You either have to source an original factory Lexus ML amp (which are pricey from a dealer), or you have to do some MAJOR stereo revamping, since the system is designed from the ground-up as an 8-ohm system (amp and speakers are 8-ohm).

ser67

Thought it might be like this - it worked intermittently this morning, but has failed again.

I've tried disconnecting the battery, to see if it will reboot.

When it did work, the sound out was fine.

Is any bit of the main ML amp serviceable at all ?

Habious

I think that intermittent functionality is a good thing. It means that it's not "dead" or "blown up".

It's probably a faulty connection, or maybe even a cold solder joint somewhere in the amp.

Serviceable? Well, that's a relative term. I've fixed things before that contained "no user-serviceable parts inside", but I've got a background in electronics, and no fear of blowing stuff up (which I've done...more than once).

If you take the trunk floor out (it's a handful of plastic plugs and a couple of bolts) you can get to the ML amp.

Turn the car on, roll down the windows, put a CD in and start poking around with the connectors.

VVTiBob

I have a PDF of the service manual (full schematic) for the amp. It's too large to post (2.2mb) in case you need it. Also there was a TSB on these amps years ago and would no longer be covered, the point is there is a history on this problem. You'll find the TSB here, post #18 https://www.clublexus.com/forums/sc-...se-help-2.html

There was a production change after this VIN JTHFN48Y#20011879

ser67

Yes, thanks for that - I have the TSB and just checked my VIN number which is JTHFN48Y400022191, so as it appears to have a production change at 11879 I guess mine has the revised amp ?

Must admit, never had it go super high, or show strange characters.

Having scanned the UK and US Lexus forums, somebody over here in the UK had similar issues with his GS and eventually narrowed it down to a faulty tel-mute on his phone car kit.

I have a parrot 3200LS installed on mine, so could it be that ??

I've contacted a parrot installer to see if he can have a look for us, ruling it in or out before contacting Lexus for a big bill....

I'm currently charging the battery, in case this is the problem.

Anyone know of a re-boot or a combination of key on/off which will reset or reboot the SC ? (I've already disconnected the battery for 30 mins to see if it sorted it - and no)

Thanks

Habious

Oh...so you have a telephone car-kit installed that's tied into the stereo's mute line?

Well, that is a useful piece of information to have!!

Yeah, aftermarket stuff is the FIRST place I'd look. (<---this is from a guy with a CarPC in his SC!!)

ser67

Woke up this morning, battery flat.

Tried to jump start with a portable battery starter (just a car battery in a case with croc-clips) and lots of clicking under the bonnet but starter wouldnt turnover. Mind you, not charged that for a couple of years.

Getting a new one (Toyota - same as one in there already) tomorrow.

I wonder if all this radio problem is down to an dodgy battery ?

TPMS was saying low pressure over the weekend, tyres were fine, drove round the block and warning went away.

Could that be it ?

Does not explain how its suddenly drained itself - unless its failed ?

Habious

You could have an electrical gremlin that's causing these problems...draining your battery, and mucking about with the mute-line in the stereo.

It's hard to tell if a flat battery is the cause, or another effect.

Please, keep is informed.

ser67

Put new battery in, and still no volume.

Now just need parrot installer to test tel-mute to rule in/out the mobile kit.

If that doesnt solve it - then it'll have to go to Lexus.

Gulp....

ser67

Left the car a few hours, with the new battery - and just stepped in with radio apparently working fine.

Turned it all off, left it again and went back and still working.

May be all sorted now - but will leave overnight and try over the weekend.

Set up appointment with Parrot installer for monday, to check tel/mute line but he seems to think its not the problem - will still pay him to check anyway.

Fingers crossed...

VVTiBob

Intermittent problems are the worst, mainly because others think you're crazy. ....good luck with the diagnostic.

ser67

Gone again - no obvious pattern to it.

Is there a service or diagnostic mode for the radio ?

How do I determine if its the head unit not giving out the signal or the ML amp not amplifying it ???

Straws & clutching at .....

ser67

Had the parrot engineer in today to see if I had a faulty tel/mute line and that was all fine.

Now today - for the first time - I can't adjust the bal/fas/bas/tre/ASL.

Not that it made any difference, as you can't hear anything anyway !!

All other radio functions are fine.

From what I've read, it now sounds more like the ML amp.

This is gonna get expensive now.......