I have a 2015 Lexus 300h. The battery went flat a few months ago – and when it was restarted the audio had stopped working (the audio remained functional but there was no output). I was advised to replace the amplifier (at a cost of £3k). But when a new battery was installed, the audio started working again. Then it stopped. Now it is in a pattern when it works for a few minutes after I start the car but then stops. I would be grateful for any ideas what could explain this. Clearly the amplifier, connections etc are working. Is it to do with static, temperature? And how could it be fixed?

 

Any moisture in the amplifier area?

 

I thought of that and put some dessicators next to it - but surely the moisture would reduce not increase once the car started?

 

I presume the new battery you had installed was the 12 volt battery and not the traction battery, right?

Did your Lexus dealer install the battery for you, or did you DIY or have an auto center replace it?

 

Yes - just done by a local garage. I had shown the problem to a Lexus garage but they hadn't been able to diagnose and only suggested buying a new amplifier.

 

Your response is confusing and lacks specifics.

You didn't precisely answer who replaced the battery, which leaves out the important timeline of events.

'What' exactly was it the local garage had 'just done'?

Did you mean that the local garage replaced the battery or did you mean the local garage diagnosed the audio problem after ['unknown'] replaced the battery and you noticed the strange audio pattens?

So, who was it that actually replaced the battery - Lexus dealer, the local garage or you?

 

Thanks - the detailed timeline is as follows. I had a problem with a weak battery a few months ago and one time, after having the car restarted by the AA, the audio stopped working. I then took the car to a Lexus garage to see if they could fix either the battery or the audio. They couldn't, told me the battery was fine and suggested a new amplifier was needed. After having the battery run down a few times I went to a local garage that installed a new battery. To my surprise, the audio started working for a period after that (a few days) but then stopped. More recently I was away for 3 weeks and the audio worked for a couple of days after I came back. Since then (the last 10 days) the pattern I described has happened: the audio works for 2-3 minutes after I start the car, and then it stops.

 

So, you had a weak battery in which you needed AA to [I guess] jump start the car for you that started the strange on/off audio pattern. But your Lexus garage (assumed to be a Lexus dealer) apparently (assumed) load tested your battery and advised you it was okay,

Was this 'Lexus garage' you took the car to a genuine Lexus dealership's service center with trained Lexus technicians?

Do you know how it was determined that your battery was okay (e.g. by load testing it)? Did you ask?

Even though the so-called 'Lexus garage' said your battery was okay - the battery ran down a few more times. Why didn't you return to the 'Lexus garage' when your battery ran down after them telling you it was okay?

Of the few more times the battery ran down - how did you get the car started?

So at some point you decided to go to some other [unknown] local garage that installed a new battery.

Is this current newly replaced battery holding up well and able to start your engine?

I'm curious how it is you know that (the audio remained functional but there was no output) when there is no audio output detected?

What is the result of testing the audio mute button on the steering wheel?

I don't mean to be obstinate - I'm just trying to make more sense out of what all has gone on before the current state of condition, which may offer some insight into possibly what the problem may be so we can hopefully help you.

 

@gerenler - Have you tried resetting the audio system? If not, at least give it a try - it certainly can't hurt and it just might take care of your audio problem...

To reset a Lexus GS audio system:
1- Put the car in 'accessory' mode (don't start the engine)
2- Let the Infotainment NAV and ML head unit fully power up.
3- While still in 'accessory' mode: Press and hold the power button on the infotainment system for 5 full seconds; this will initiate a reboot of the audio system.

Let us know the results.

I'm curious - Have you looked to see if the well in the trunk where the amplifier is mounted has taken on any water? What was the results of your inspection?

Lastly, if the problem turns out to be the amplifier, a used perfectly good replacement Lexus amplifier is usually available on eBay for $750 - $850 USD, a lot less than the £3k you were told.

 

Thanks for the detailed, response, appreciated. Yes that is what happened. The Lexus garage was a fully official one (and yes did load testing I think) but about an hours drive from me, so I wasn't keen to go back and forth too much. I had to call the AA several times to restart the car. The new battery works fine. The audio appeared to be working (ie I could see and control all the inputs, except for volume control, and there being no actual audio output). I tried various options on the steering wheel but to no effect. The boot where the amplifier sits is fairly damp - which is why I put some dessicants there as a potential solution. But oddly the audio worked fine after a particularly rainy/damp spell so that is probably not the cause.

 

Did you try resetting the audio system? If not, at least give it a try - it certainly can't hurt and it just might take care of your audio problem...

To reset a Lexus GS audio system:
1- Put the car in 'accessory' mode (don't start the engine)
2- Let the Infotainment NAV and ML head unit fully power up.
3- While still in 'accessory' mode: Press and hold the power button on the infotainment system for 5 full seconds; this will initiate a reboot of the audio system.

Let us know the results.