I have a 2003 Lexus LS430. Last year at Best Buy I replaced the Lexus stereo unit with a Pioneer DMH-1500NEX stereo system. Best Buy also installed a rear view camera, which displays on the stereo display screen. Everything worked fine for a year.
In April 2023 my battery died from a bad cell and was replaced under warranty. After the new battery was installed my stereo screen lights up but there is no sound from the speakers. Also, the rear camera no longer displays.

My stereo is under warranty from Best Buy but they lost their car audio technician and will not hire a new one for a couple of months (extended training required). I would like to try to fix this problem myself if I can.

I checked all the fuses in the trunk and they are good. I do not know how to access other fuses.

I looked at the settings on the Pioneer screen and do not see any error codes.

I went back to Advance Auto where I got my battery and a guy there said that when an aftermarket stereo system loses power, like when the battery is replaced, the stereo system has to be reset somehow, but he did not know how.

On the pioneer screen there is an option to restore defaults, which I did, Still no sound.

Is there a switch or a fuse somewhere else I need to fix to get the sound back? The speakers are the original Lexus speakers. Only the stereo unit in the dash was replaced.

Thanks for any advice anyone can share.

 

Two Audio System fuses #33 and #36. They are row-1, row-4 on the right most column in the passenger-side panel.

 

Thank you for that suggestion. I pulled all the fuses on right side. All fuses are in good shape. Must be something else.

 

Took a quick look at your manual and shows the reset button and procedure. If that doesn't work disconnect the battery for 5 min to see if fix.

 

I found the reset button on the Pioneer stereo panel and hit it. The stereo reset itself. But still no sound. I finally got into the car shop at Best Buy and will report later what they did to fix the sound.
Update June 24, 2023: Best Buy technician says stereo is producing sound but sound is not getting past the factory installed amplifier in the trunk. He thinks the battery going bad and replacement may have damaged the amplifier. I need to take the car home and remove all the covers in the trunk to get to the amplifier and get the part or model number off it and then find a replacement online and bring back to Best Buy and they will install for free.
By the way disconnecting the battery for 5 minutes caused the rear view camera to start working again.

 

The manual and reset is on your pioneer unit you said you had. Bottom right is your reset.

 

My local Lexus dealer charges $3,100 just for the amplifier part not including installation.
I think I can get the amp online for about $1,500. I opened the trunk area to look at the current amp. It is tucked in pretty far up inside the back of the trunk and too complex for me to remove. I could not find a part or model number on it but believe it can be looked up with my VIN. I did not see any fuses near the amp. I guess my only option now is to buy a replacement amp and have Best Buy install it.

 

It is unlikely that the 12 volt battery going bad and replaced caused the amp to go bad. It is possible but not likely. It would mainly be a lack of capacitors charged up that are on there way out anyway but generally still work just poorly when voltage put back on. Is yours the ML amp or not? Also ask Best Buy if they injected signal directly into the amp and then no output. You need to check and make sure the constant 12 volt and the ACC switch 12 voltages are there. If voltages are there and with signal injected and no output then the amp is dead. Take the amp out and send it off for repair for a fraction of what you are talking about. Before when I looked at your manual it talked about having to reset the unit in the beginning and if battery is replaced which led me to believe that should have fixed the problem. Anything can happen though but just make sure the proper diagnostic steps are taken without making a costly mistake. Also if it is the ML system I know there is electronic switching between sources to go to amp. Signal has to be injected at the amp for diagnosis to make sure amp is bad.

 

I replaced the OEM radio and CD player with a Pioneer touchscreen radio at Best Buy. Initially worked great. When my battery went bad and a new battery was installed, the radio display worked but there was no sound from speakers.

All fuses checked and were fine. Initial diagnosis - a dead amplifier. Amp is in the trunk in a hard to reach spot between the right fender and wall of trunk. Youtube videos show how to remove.

Ordered a used amp on eBay (about $130 USD). Took to Best Buy Car Audio shop.

Technician could not get new amp to work. He told me he didn't think it would do any good but he removed the "brain" a small rectangular box containing circuits that is behind the dash and connects the radio to the car. He had a replacement one and installed it and the sound returned. My original amplifier works. It was the "brain" object that needed to be replaced.



If your Lexus speakers stop working, before removing or replacing the amp, have a technician try replacing the "brain" unit in the dash to see if that fixes the problem.

From the Best Buy receipt the "brain" part is called - PAC - Radio replacement and steering wheel control interface for Select Toyota, Lexus, and Scion Vehicles Black/Blue, Model No.RP4.2-TY11, SKU4972400.

Price for the part was $159.99 plus $11.20 sales tax.

I hope this helps others.