Originally Posted by 0taku

My concern is that there may be some issue that causes this to happen which was not found!

Originally Posted by 0taku

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.

Originally Posted by 0taku

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!

Originally Posted by jimmyzyr

hey i bought a 2014 gs350 a month ago from a dealer( i live in australia). I seem to have the exact same issue after bringing my car to a friend who runs a car workshop and as soon as i saw your post i recognised the exact same code he told me.

I wonder if this has been fixed and how it was fixed?