Howdy ClubLexus,

I am on my 2nd ML amp in 2014 IS 350. Previous one had no sound and never came back. I did not know about error codes then. Lexus replaced the amp and said it was bad.

This problem with the 2nd ML amp only started in August after I disconnected the battery to install the performance air intake (instructions said to disconnect battery first).

NEW ML amp less than 1 yr old...
I have an intermittent short circuit present at times when the vehicle starts up. CODE: B15C3

PROBLEM: Each time the car is started the audio may be ON/WORKING/THERE IS SOUND or OFF/NO SOUND. When sound is not working the diagnostic system shows error code B15C3 is active. When audio is working the error code is NOT active. Either way the history shows B15C3 on July 13, 2020. The audio never drops out while driving if it was on when the car started. The audio never comes on while driving if it was off at startup of car. The situation only changes if the car is turned OFF and started again. At this time it decides whether to be ON or OFF (and show active code). Switching the stereo off/on with the **** makes no difference. Only turning off the car provides a chance that the situation will change.



MOST COMMON SCENARIO: sounds working all day on several driving trips. Car is parked in garage. Sound is working when car is parked. Next morning no sound. At some point later subsequent uses of the car sound often comes on. The change from sound to no sound happens when the car is totally sitting still and not driven. It has nothing to do with the car being moved.



According to documentation: B15C3 LEXUS Possible Causes

Faulty Speaker ( it does not specify which one)

Speaker harness is open or shorted

Speaker circuit poor electrical connection

Faulty Navigation Receiver Assembly

Faulty Stereo Component Amplifier Assembly



I may start the car 3-5x in a row and there is sound. Then later in the day I use the car and no sound. The next day or next time I drive it may be back. (the car has not been moved) There is no specific pattern as to whether the sound is working or not. It SEEMS TO BE ABOUT 80%-90% of the time SOUND WORKING and only 10%-20% NO SOUND.



I ran some tests.

At times when there was no sound code B15C3 came up as "present".

While the code was present (no sound):

I tested disconnecting speakers and rerunning the diagnostic to see if a bad speaker was causing the issue.

I tested: front door speakers, rear deck speakers and and sub

rear deck. Disconnecting those speakers and rerunning diagnostic yielded NO CHANGE.



My testing would seem to rule out the front door speakers, the rear deck and the sub. I did NOT try disconnecting the rear door speakers or those in the dashboard.

The frustrating thing about this is that it is unpredictable as to whether the sound will be ON or OFF(with present code). The most common scenario for it to be off is in the morning on 1st use of the car. The problem is intermittent which makes it difficult to troubleshoot. If you power on and there is no sound and the code is present do all the testing you can because a subsequent power on/off may bring back the sound.

HAS ANYONE HAD THIS PROBLEM? Could it be the amp... AGAIN?

PS: I have the levinson system and nav. I thought about just going aftermarket with JL audio amps and Focal speakers, BUT the stereo shop told me that they CANNOT interface with the head unit. Is this true? They said they could connect to the output of the ML amp.. which defeats the purpose of getting rid of it because it has problems...

Has anyone successfully BYPASSED (removed) the Mark Levinson amp and did aftermarket?
Thanks!

 

I am pretty sure when you buy parts from Lexus there is at least a 6 month - 1 year warranty on it, go back to the dealer and tell them what happened before you start looking into aftermarket solutions. Pretty crazy that this ML audio option is $2k-3k and has this many issues.

 

I have ML it's not $2-$3k standalone option it's bundle with Navigation yeah still expensive but I have same yr 2014 so far no issue knock on wood.

 

I am bringing it in to Lexus tomorrow, but I am concerned about their ability to troubleshoot it. The amp was replaced under warranty before. The previous problem was similar..

I wanted to just go aftermarket, but was told that was not possible.. So I am digging for information that will help...

 

If the Amp was replaced under warranty, then it's only under warranty for the remainder of the warranty period...unfortunately.
Given that is has been less than a year, maybe talk to them about "Good-willing" a warranty replacement of the Amp.
If you're a good customer of the dealer, they should have an issue with this.

The ML system has been pretty good to date, it's very common for the non-ML amps to go, but yours is the third ML amp I've seen go on the forum.
I suggest giving this thread a read: https://www.clublexus.com/forums/is-...r-failure.html
One member used an alternate part number Lexus Amp on his ML equipped car to resolve an intermittent no sound issue.

There may be more info about simply replacing the stock Amp here:https://www.clublexus.com/forums/bui...reo-build.html
The build thread is for the non-ML system, but may still have info applicable to the ML system. It's not like the systems are night and day, it's just that one has more speakers.

 

United Radio fixed my ML Amplifier. great work and great service!!!

 

@Gekko I think something happened to the web address you pasted. I wonder if the name of their site is something that is being censored.

 

Car will be at lexus until at least tomorrow. My big concern is that if this is 2nd amp to go bad that there is something causing it. it seems like this might be very hard for them to find. So, even if they do replace the amp... what if the same thing happens again..?

I do not know if this is true:
One person said online somewhere that all of the MLs go bad due to parts that degenerate over time. So even new old stock has aged and those will not last.


Certainly I will update you all when I get the car back.

 

check your PM.

 

Thanks...added the website address to the stickied thread about Amp failure. Had to get creative as it was still being censored.

 

Ok, here we go. This will bake your noodles. After a week in the shop @ Lexus.. They found the problem. It is coming from the Telematic Sensor. This is something that is behind the steering column. Lexus dealer with help from central corporate lexus techs determined that the telematic sensor is interfering with the stereo and is the cause of this problem. They also verified that the previous amp was bad and the new amp is ok. They are replacing the telematic sensor under warranty and it will take a couple of days.

All of the speaker connection troubleshooting in the world would not have helped in finding the problem. My service advisor had never heard of this problem before.
The good news is it will be fixed and back in a few days.

Pretty crazy, huh?

BTW: if anyone is on the fence about the lexus performance air intake... Get it! It does make a difference in power when accelerating. It is actually quieter than the stock one also.

 

Great news. When you get the vehicle back, if they provided you the part number for the Telematics Transceiver on the invoice, if you can post it that would be great.
For your reference, it should be item number 6 in the below diagram they are referring to.
Just as a note, the Telematics Transceiver is only found on US vehicles (in North America) as it only applies to vehicles that have Lexus Enform and/or Safety Connect. So if you have a Canadian vehicle and you have this problem, this fix will not work for you, as the vehicle simply does not have that component.

The Transceiver does have the ability to mute the audio coming out of the radio and it uses the speaker on the top right of the dash to provide you with audio when using Safety Connect.
I'm a little surprised this was the issue, but if it fixes it, so be it. You will note this component was not on the possible faulty items list, which also makes it strange that this is the issue.
But at the end of the day it does have the ability to mute the audio from the radio.

 

Sasnuke,

Great info. . The fault code is a speaker short.
Now it makes sense how this happened
"The Transceiver does have the ability to mute the audio coming out of the radio and it uses the speaker on the top right of the dash to provide you with audio when using Safety Connect."

The transceiver caused the fault in the speaker line. Your sentence above explains how that is possible. Its connection with the top right speaker is where the intermittent fault originated from.
That is why the amp saw this code: B15C3: Possible Causes Faulty Speaker ( it does not specify which one)

Makes sense now.

I will post the info when I get the documentation. It will be a warranty fix, but the info should be on the documentation.

In this process I learned that the head unit communicates with the ML amp via an encrypted digital signal. That is why aftermarket amps cannot interface. You can take the speaker outs of the ML amp and drive other amps.. but, you cannot bypass the ML amp. The volume control sends a digital command to the ML amp to raise or lower the gain, so volume control does not exist at the preamp level out of the head unit. IF ANYONE IS WONDERING ABOUT AFTERMARKET AMPS REPLACING THE ML AMP = NO. END OF STORY. NO. 2 stereo shops said they could over the phone, but they did not realize how the head unit works until later.

There are kits that replace the sub by taking the sub speaker line and connecting to an amp and a sub, but that is all you can do.

I am waiting for this to arrive: PPE Engineering 340 Stainless Lexus IS350 Headers w/ Black Ceramic w/ titanium wrap.
This is supposed to be one of the best performance upgrades available.. I will let you know.

 

They changed their minds. After 2 weeks @ dealership they determined that the amp was bad and replaced it. They said it was not the telematic sensor.

 

What?!?! I'm shocked!!
OK, not really...it seemed strange that was the issue. It looked like an amp all along, so at least it's getting fixed now.