Only 1x USB Serial Bus for data? "UI_a112 - USB device malfunction - I/O Error"

[happyevil]

On my 2019 Model 3 Stealth Performance (2x USB-A ports in the front), I've been experiencing this dreaded "UI_a112 - USB device malfunction - I/O Error" for some time now (I want to say "years").

My list of devices plugged into the 2x USB-A ports consisted of:

• TAPTES USB Hub 5 in 1 Ports
• TAPTES Wireless Charger
• Samsung FIT Plus USB 3.1 Flash Drive 256GB (for Music files currently, but I've tried other USBs for this specific need and still experience the same issue)
• Samsung PRO Endurance 128GB (MB-MJ128GA/AM) connected via a "geekgo SD Card to USB Reader" (for dashcam/sentry)

Most of the time, all my devices work fine and I'm able to play music off one USB, charge my devices, and have the other USB capturing dashcam/sentry. But other times I get the UI_a112 error. When this happens, my USB for dashcam/sentry and wireless charger works fine. But, my USB for music does not get detected and does not show up as an audio source. I'll either have to unplug/replug it in a bunch of times to get it to work, OR just hope that when I drive the car the next day or later in the week that it magically works again.

I tried unplugging the TAPTES USB Hub and TAPTES wireless charger altogether, leaving just the Samsung 256GB USB on the left USB port, and Samsung 128GB SD Card on the right USB port. But, still the same issue (potentially not as often as before?).

I've scoured this forum + other sites and found suggestions such as restarting the computer, changing the HUB, changing the USB sticks, and even getting Tesla to replace the MCU.

So I went ahead and scheduled a service center appointment. Here was my experience:

• Front desk service guy suggested that I should be using Tesla specific USB drives. (I'm a little weary to believe that this is the fix. Their 128GB USB stick won't fit all the music files I have). Front desk service guy suggested I speak to their service tech lead before I have them take the car in for inspection (thus getting charged the labor/diagnostic fee).
• Service tech lead mentioned that the car's computer has only one serial bus for data, and that it splits that to the 2x front USB ports. So technically the car only supports 1x USB device for data, and was told that it cannot handle multiple USB sticks transmitting data. I'll need to choose whether or not to use the USB for dashcam/sentry OR music. Not both.
  • I've asked him what his thoughts were a single USB drive but with multiple partitions (dashcam sentry, music, etc). He said I can give it a shot but he's seen cases where customers have ran into this same error even in this scenario.

If what he said is true, then this is disappointing considering I don't think there's any mention in the manual of this limitation (or at least I think there isn't).

I'm posting this to see if anyone else can confirm if this is how the USB ports > serial bus / data transmission > MCU connectivity works and/or if others had different experiences with this same error.

 

[Kevy Baby]

On my 2019 Model 3 Stealth Performance (2x USB-A ports in the front), I've been experiencing this dreaded "UI_a112 - USB device malfunction - I/O Error" for some time now (I want to say "years").

[snip]

So I went ahead and scheduled a service center appointment. Here was my experience:

• Service tech lead mentioned that the car's computer has only one serial bus for data, and that it splits that to the 2x front USB ports. So technically the car only supports 1x USB device for data, and was told that it cannot handle multiple USB sticks transmitting data. I'll need to choose whether or not to use the USB for dashcam/sentry OR music. Not both.
  • I've asked him what his thoughts were a single USB drive but with multiple partitions (dashcam sentry, music, etc). He said I can give it a shot but he's seen cases where customers have ran into this same error even in this scenario.

I can't answer the question about the number of buses, but I can tell you the car CAN handle multiple data sticks. I actually have three data drives running in my car:

• A Samsung T7 partitioned into two volumes: one for music (just under 13,000 tracks, a large number of which are FLAC files) and one for Teslacam.
• A 128GB micro SD in a @Navak splitter. I was a beta tester for this item and just never removed the SD card.

I can see both music volumes in the car: I just have to select which "Device" I want to use. But I know more than one data drive can be accessed at a time as I can save cam footage at the same time that I am listening to music from the USB drive.

I too have a 2019 and have a Navak splitter in each of the front USB ports (one regular and the one with the built-in micro SD port). Unfortunately, the Navak is no longer available (too bad: it was a great product). But since you already tested removing the Taptes hub from the equation (not a fan of their products), this is not that important.

When you did have the two volumes plugged directly into each port, COULD you get both devises to work (even if not all the time)?

One thing I would try is to get two completely new thumb drives. No need for the SD card in a tray: there is no advantage to this setup and just introduces more points of possible failure.

 

[happyevil]

I can't answer the question about the number of buses, but I can tell you the car CAN handle multiple data sticks. I actually have three data drives running in my car:

• A Samsung T7 partitioned into two volumes: one for music (just under 13,000 tracks, a large number of which are FLAC files) and one for Teslacam.
• A 128GB micro SD in a @Navak splitter. I was a beta tester for this item and just never removed the SD card.

I can see both music volumes in the car: I just have to select which "Device" I want to use. But I know more than one data drive can be accessed at a time as I can save cam footage at the same time that I am listening to music from the USB drive.

I too have a 2019 and have a Navak splitter in each of the front USB ports (one regular and the one with the built-in micro SD port). Unfortunately, the Navak is no longer available (too bad: it was a great product). But since you already tested removing the Taptes hub from the equation (not a fan of their products), this is not that important.

When you did have the two volumes plugged directly into each port, COULD you get both devises to work (even if not all the time)?

One thing I would try is to get two completely new thumb drives. No need for the SD card in a tray: there is no advantage to this setup and just introduces more points of possible failure.

Yes, the two volumes/drives plugged directly into each port (no Hubs) actually works MOST of the time. Even with the Taptes Hub, it worked at least half the time.

I went with the SD card option a couple years ago for dashcam/sentry due to the write intensive nature of dashcams and me learning my lesson about it after my numerous USB sticks eventually got stuck in read only after hitting their max write cycles.

Perhaps I could opt for a large enough SSD USB that could house both (two separate partitions).

 

[Kevy Baby]

Perhaps I could opt for a large enough SSD USB that could house both (two separate partitions).

I am a fan of this. I have a 1TB Samsung T7 and I highly recommend. I have it partitioned at 700GB for music and 300 GB for TeslaCam

FWIW, I had two 256 GB SanDisk Cruzer drives for over 2 years with zero issues. I honestly believe that your SOURCE for the drive is equally as important as which drive you get. I would never get something like this from Amazon as I do not trust their supply chain. Even top rated names are easily counterfeited so even if you bought a reliable name, you are never sure if that is what is actually inside. I bought the two drives from Costco (whose supply chain I trust) and I believe that this is part of the reason I never had an issue (this particular drive is no longer available at Costco). The only reason I switched was capacity (for the music volume).

 

[happyevil]

I am a fan of this. I have a 1TB Samsung T7 and I highly recommend. I have it partitioned at 700GB for music and 300 GB for TeslaCam

FWIW, I had two 256 GB SanDisk Cruzer drives for over 2 years with zero issues. I honestly believe that your SOURCE for the drive is equally as important as which drive you get. I would never get something like this from Amazon as I do not trust their supply chain. Even top rated names are easily counterfeited so even if you bought a reliable name, you are never sure if that is what is actually inside. I bought the two drives from Costco (whose supply chain I trust) and I believe that this is part of the reason I never had an issue (this particular drive is no longer available at Costco). The only reason I switched was capacity (for the music volume).

The Samsung 256GB USB (music) I sourced directly from Samsung (i linked via Amazon in my original post cause I had it already open at the time). The Samsung 128GB SD Card + adapter (dashcam/sentry) was from Amazon. Whenever I experience the error, it's always the music USB that fails to read, while the dashcam/sentry SD Card + adapter combo always ran fine.

Not discounting what you said at all (there's definitely truth to it). I just don't think it's the root cause of this particular issue. Both USB + SD Cards work fine every time when I'm plugging it into my other devices such as desktop, laptop, etc. Which is what lead me to the question in my original post about the existence of just 1x Serial Bus potentially not being able to handle 2x USB ports transmitting data into it.

At this point, we know that it COULD handle multiple data sticks, but wanted to verify if that it can from a technical perspective.

 

[ElectricAnt54]

The usb-a stick tesla provides for dashcam in newer cars is a $28 Samsung bar plus. When bought from Samsung, they have 5 year warranty and are made for extreme heat and cold. They use the same endurance memory chips as the endurance line of products but don’t advertise the fact.