LX stereo no sound -fixed (1 Viewer)

[PDoyle]

There is a ton of wiring under the carpeting under the front seats. I stuck my arm under the front seats to clean up some (gold fish) food spillage.
The next day I drove around with no sound coming from the stereo and of course thinking I needed the $700 replacement amp.
I checked fuses and none were blown, so it had to be a connection issue.
After reading up on amp failure and replacement I found the wiring for the stereo and the display goes under both seats.
Long story short and it was the wiring under the passenger side seat. I pulled the battery cable and kind of pulled the wire loom that sits under the carpet upward, replaced the battery cable and it worked.
The two pics attached are what I saw when there was no sound. DSP display was blank and the blue tooth sound display wouldn't move.
I found a test for the multi display. I didn't need to use this but it would be a good test for future use.
2013-2015 LX570 w/ Multi-Display
(1) Start the engine.
(2) While pressing and holding the "INFO" switch, Turn your lights on and off three times (3x).
(3) Diagnostic mode starts and the "Service Menu" screen will be displayed

The moral of this story, don't clean under the seats.

 

[LXstatic]

I have this exact problem. I had a bad sunroof leak in floorboard. I cleared all that up, dried out the carpeting and underlayment. I am thinking that I may have pulled something out when i pulled on wiring harness/loom at door sill plate under carpet. What exactly did you do to fix? Just wiggle the wires? Or do you think it is a matter of disconnecting the battery cables for 15 minutes?

 

[PDoyle]

I would pull a battery cable off and gently push down on what looks like the wire loom under the seat.

 

[radman]

Came here to drop a fist bump.
I was looking for a set of keys over the weekend and had checked the massive void under both seats. No audio and no response from the volume controls (both steering wheel and dash).
I moved the passenger seat all the way forward, pressed in and jiggled all the connectors I could see, and then restarted the rig. All back to normal now...

 

[cubaniche]

Does anyone have the diagram for the MOST bus devices? I have no sound with B15D0 code. I sent my amp out, and was told there's nothing wrong with it. Next, I replaced the multi display controller because the screens weren't coming on and that controller is part of the MOST bus so if it's bad it would interrupt that bus signaling and prevent sound etc. Brand new co trolley didn't fix it either. I've checked all the fuse under the hood, and the two locations in the cabin (driver and passenger side fuse boxes) but none of the fuses are blown.

I'm trying to identify what other devices might be on that MOST bus to continue troubleshooting. I know the head unit, amp, and multi display controller are on it but I don't know what else is connected to it that may be interrupting signal loop from completing.

 

[Plplayer]

Same issue. No sound, no power to rear monitors. Took it to the dealership and the audio came back on and they said there was nothing they could do. It had to be an active issue. I unplugged the negative battery cable for 10 minutes and the audio came back on for a while and is now back out. No clue as to what it could be. Tried to jiggle the wires under the seat and checked if the harnesses were seated. Everything was and still no audio

 

[Rrb1981]

Does anyone have the diagram for the MOST bus devices? I have no sound with B15D0 code. I sent my amp out, and was told there's nothing wrong with it. Next, I replaced the multi display controller because the screens weren't coming on and that controller is part of the MOST bus so if it's bad it would interrupt that bus signaling and prevent sound etc. Brand new co trolley didn't fix it either. I've checked all the fuse under the hood, and the two locations in the cabin (driver and passenger side fuse boxes) but none of the fuses are blown.

I'm trying to identify what other devices might be on that MOST bus to continue troubleshooting. I know the head unit, amp, and multi display controller are on it but I don't know what else is connected to it that may be interrupting signal loop from completing.

Same issue. I lost audio and rear entertainment system. It did happen around the time I installed and then removed some floor mats. I have tried to make sure all wire looms are properly connected. My amp fans are spinning. Really frustrating to say the least. 2016 (just bought it with 116k miles, extremely well maintained at the dealership, single owner). Wife isn't happy about it. One thing mine does is that it makes a "click" or light "pop" sound about every 5 seconds. Barely audible.

 

[jflow88]

Same issue. I lost audio and rear entertainment system. It did happen around the time I installed and then removed some floor mats. I have tried to make sure all wire looms are properly connected. My amp fans are spinning. Really frustrating to say the least. 2016 (just bought it with 116k miles, extremely well maintained at the dealership, single owner). Wife isn't happy about it. One thing mine does is that it makes a "click" or light "pop" sound about every 5 seconds. Barely audible.

an engineer at United Radio sent me this, received it from Panasonic (makes the RES). also when i originally brought my LX to the dealership, they tore apart the center console and referenced some connectors around the cup holder area. in the same effort everyone here is experiencing, when i sent my amp to United Radio and discovered it wasnt broken, a tech from their team called me and said he heard there is another connection under the carpet somewhere that could be the trouble, he didn't know where, and i haven't found a diagram that detailed where all those might be, but could align with your floor mat experience

 

[Rrb1981]

an engineer at United Radio sent me this, received it from Panasonic (makes the RES). also when i originally brought my LX to the dealership, they tore apart the center console and referenced some connectors around the cup holder area. in the same effort everyone here is experiencing, when i sent my amp to United Radio and discovered it wasnt broken, a tech from their team called me and said he heard there is another connection under the carpet somewhere that could be the trouble, he didn't know where, and i haven't found a diagram that detailed where all those might be, but could align with your floor mat experience

View attachment 3815718

Thanks. I just pulled the Mark Levinson amp. Plan is to send it to OEM Auto Audio to be bench tested. The fans spin. When I disconnect the amp, the annoying faint "pop" noise goes away. I does not go away when I disconnect the RES module under the passenger seat (red plug). I am holding out hope that it is just the amp. Otherwise, I guess I'll be bringing it in to Lexus with low probability that they can resolve the issue.

 

[Rrb1981]

Thanks. I just pulled the Mark Levinson amp. Plan is to send it to OEM Auto Audio to be bench tested. The fans spin. When I disconnect the amp, the annoying faint "pop" noise goes away. I does not go away when I disconnect the RES module under the passenger seat (red plug). I am holding out hope that it is just the amp. Otherwise, I guess I'll be bringing it in to Lexus with low probability that they can resolve the issue.

Update:

Amp was bad. OEM Auto Audio said liquid intrusion. Apparently all it takes is a very small amount. To my knowledge, we did not spill any liquids, but we did purchase the vehicle used a couple of months ago. Not happy about the $675 repair cost, but relieved that this is (hopefully) the issue.

 

[cubaniche]

Update:

Amp was bad. OEM Auto Audio said liquid intrusion. Apparently all it takes is a very small amount. To my knowledge, we did not spill any liquids, but we did purchase the vehicle used a couple of months ago. Not happy about the $675 repair cost, but relieved that this is (hopefully) the issue.

I've heard from different sources that the amp can get wet from drainage out of the cool box if equipped. Not entirely sure how that would happen exactly. Good to hear it was repairable.

 

[Rrb1981]

I've heard from different sources that the amp can get wet from drainage out of the cool box if equipped. Not entirely sure how that would happen exactly. Good to hear it was repairable.

Ours doesn't have a cool box so not really sure.

 

[PDoyle]

When you pulled the amp out did you remove a plastic cover on the carpet that sat partiality over the top of the amp?

 

[Rrb1981]

When you pulled the amp out did you remove a plastic cover on the carpet that sat partiality over the top of the amp?

Full confression: I used a box cutter to enlarge the opening around the amp. Some other posts had mentioned this as some amps fail from overheating. What I cut is not visible, even when moving the seat all the way forward or all the way back. I also had to make a small slit on the driver side door of the amp to get that third mounting screw.

I am happy to announce that the stereo is working well now with the repaired amp.

 

[PDoyle]

I did the same thing.

 

[cubaniche]

Well, I figured out the source of my sound/video issues. After replacing the multi display controller under the passenger seat and sending the amp out for repair and finding out the amp was good, I had to start looking at electrical. Found this:

One of the pins was so corroded it fell off. Thing is everything is dry. Sunroof seals good and the drains are clear. I've only owned my 14 for about a year and half so maybe this was already present and juat got worse over time. I've never had wet carpets or musty water smell. The LX is also always parked under cover. So, I believe this was preexisting and essentially a ticking time bomb. I was able to source a whole new passenger side floor harness and am in the process of swapping that out. Center console is partially disassembled as well as front passenger and rear seats are out to be able to pull up the carpet and get to the wiring harnesses that run from the right side sills, up the B pillar and also halfway across the floor to the console and rear controls.
The new one looks clean. It ce out of a 26k mile 2014 that wrecked.

Hopefully this is the actual problem. I can't imagine that it's not when the pins were so corroded. Even if it's not, at least I know I fixed a bad harness.

 

[jflow88]

@THEBLACKCRUISER

 

[THEBLACKCRUISER]

Well, I figured out the source of my sound/video issues. After replacing the multi display controller under the passenger seat and sending the amp out for repair and finding out the amp was good, I had to start looking at electrical. Found this:
View attachment 3866800

View attachment 3866802

One of the pins was so corroded it fell off. Thing is everything is dry. Sunroof seals good and the drains are clear. I've only owned my 14 for about a year and half so maybe this was already present and juat got worse over time. I've never had wet carpets or musty water smell. The LX is also always parked under cover. So, I believe this was preexisting and essentially a ticking time bomb. I was able to source a whole new passenger side floor harness and am in the process of swapping that out. Center console is partially disassembled as well as front passenger and rear seats are out to be able to pull up the carpet and get to the wiring harnesses that run from the right side sills, up the B pillar and also halfway across the floor to the console and rear controls.
The new one looks clean. It ce out of a 26k mile 2014 that wrecked.

View attachment 3866815

Hopefully this is the actual problem. I can't imagine that it's not when the pins were so corroded. Even if it's not, at least I know I fixed a bad harness.

Tysm! Im gonna check tomorrow and see if any pins broke off, wish me luck

 

[cubaniche]

Tysm! Im gonna check tomorrow and see if any pins broke off, wish me luck

Good luck! I'm in the process of putting it all back together now. I'm using dielectric grease in the connectors to try and insulate them better from moisture etc and hopefully avoid this issue in the future.

 

[cubaniche]

Ok, that was it! LX has sound again. I insulated the harness connectors with some dielectric grease to try and prevent this water intrusion should it happen again. Now to putting the interior back together.