Radio Screen keeps going off in this 2016 Tahoe and setting MOST Bus Faults

The MOST Bus is what carries all the information from module to module in the radio system of newer GM vehicles. It's designed in a way that even the slightest fault with the information can lead to very strange looking issues as you can see here with the touchscreen turning on and off.

[@josedejesusvelazquez6863]

PD. - I forgot to mentioning that if you, set this link in quotation marks in your bowser and there you will find very valuable information on this topic “MOST bus with a Ring break GM”.

[@GroundedDiagnostics]

Never seen anything like this. Fascinating stuff.

[@15066bas]

When there is a break, a new surrogate is assigned, in this case no3 the amp. That means break is the module ahead of the new surrogate being the HMI.

[@germ294]

Man, you are legit. I really appreciate you sharing your experiences in automotive repair. You rock!

[@bennie1634]

Well , I know that the dataspeed of the MOST is at 50Mbps , so hundred times the speed of a high speed GMLAN ,so not easy to catch the signal on a scope . Enjoyed your approach to this problem and watching the rest of your videos . Keep up the good work !!

[@russellhltn1396]

There's also a MOST150. But it looks like the Automotive Picosope only goes to 20MHz. I just glanced at the specs, but this seems to be closer to Eithernet than to what's normally in an automotive system. The Pico may be a bit out of it's league here.

[@rookiediagnosticsandrepair5956]

That is some sci-fi stuff! MOST signal does not look digital at all. Very well presented.

[@JBlake-moon-shdo]

Lol. Jake that is a very typical audio signal your looking at. Unplug any speaker hook the pico to it and you will see the same wave form. You may notice it changes to the sound. Great video.

[@Discretesignals]

I wondering if the sample rate of his scope is set too low and its aliasing the signal. I'd crank the rate up as high as it would go and see what the waveform looks like. Most bus has a high baud rate, so you need a fast scope to see it.

[@DependableAutoTruck]

great video haven't watched many of your videos just found the channel short time ago but wanted to tell you so far great content really like how you explain kinda reminds me of Ivan at PHAD

[@PineHollowAutoDiagnostics]

Great info and troubleshooting process! This is cutting edge stuff here, learning a lot. Could someone diagnose this system without having the special Bosch MOST kit?

[@elora2525]

If the most bus in GM is fiber optic like BMW is getting a bus MOST jumper from BMW probably much cheaper than that kit he mentioned. BMW initially had the OPPS head that measured light attenuation attenuation but in the real world it was not a good test as just jumping the fiber optic

[@meganhazen3978]

You’re videos are very informative 😊love them keep them coming ❤!

[@durranibrothers8315]

Hello sir I have same problem but I dnt know what’s problem

[@advancedleveldiagnostics]

Excellent information Thanks! Are you a Gm dealer tech? Did you put a scope on the other car to see if it's the same, really don't want to buy that tool?

[@advancedleveldiagnostics]

@@autodiagyt Thank you, I just looked up the tool it's not as much as I thought it would be. maybe I'll buy myself a present.

[@rogertarrant4331]

My 2016 Silverado 2500HD is having the exact same issue right now. I bought an aftermarket stereo that allows me to keep the factory Bose setup and the screen works but has no sound.

[@rogertarrant4331]

How do you bypass the HMI to get the speakers to work? I just want to do it to make sure that is my issue

[@abztvbaxley8457]

Hey my screen on my 2019 gmc Yukon want go down after you open it to get to the compartment behind the screen. It’s like it’s got something blocking it from going back down. Any idea what that kind be?

[@jimnoll7728]

I had my radio not working right an did you just turn off the radio over night it fixed mine 2015 chevy

[@JBlake-moon-shdo]

Those were typical audio sinusoidal wave forms probably one for each channel "2" stereo. 👍

[@bradz5202]

New to your channel. Great job keep up the good work!

[@bas2876]

Question:Always thought Most is an optical bus like glassfiber, how did you scope that then? , but mayby I'm wrong. Great video by the way!

[@bas2876]

Thanks,did'nt know that,I'm used to the eurostyle optical fiber system.

[@Sergio09354]

Hello new subscriber here. i don't comment much but i always watch your videos. this one is excellent explaining the way to test it thanx for sharing your wisdom. keep up the good work.

[@jeffsnider3588]

As a retired Engineer this system seems over complicated, so are dealer technicians trained to perform diagnosis like this.

[@brandonnguyen9421]

What if the radio screen is completely dead and the info screen on your speedo says audio off??

[@brandonnguyen9421]

@@autodiagyt would you say most likely HMI module?

[@RentalCarsandYallCousins]

I have that issue. Did you get it figured out?

[@reanacook8504]

Dealing with the same problem. Did you get it figured out?

[@armandoleon6828]

Was it the HMI for you?

[@adelalshammary109]

Love auction cars

[@EATSLEEPFARM]

Are you in KY or TN?

[@redsoundaudio6323]

Hi did you replace it after all?

[@autodiagyt]

Yes they came back about 6 months later and got the new HMI.

[@michaelrobertson6774]

Did it fix the problem after replace

[@autodiagyt]

@@michaelrobertson6774 yes

[@ericflores5748]

Did you were able to fix the problem

[@ericflores5748]

@@autodiagyt can you share the part number 🙏

[@martincuevas9193]

2016 push start?

[@autodiagyt]

Yes you can have a 2016 with push start.

[@josedejesusvelazquez6863]

Hi Dear Friend, I really like your videos and I also enjoy them a lot and study them too, but it is very difficult to do this because I have to put the audio at the highest level (100%). This causes that when the KZbin commercial comes on, my eardrums burst. Hopefully you can remedy the situation. Thank you and receive a big greeting from Tijuana. 🇲🇽 Mexico 👍👍👍

[@marshall1157]

They need to go back to a single entertainment UNIT.