U0100 code after reflash back to stock

[keithk831]

I reflashed my car back to stock today (from a Unitronic tune), and got a DTC of U0100 immediately afterward. No check engine light and no driveability issues (drove about 10 miles), but I see it on my OBD2 scanner and on VCDS. It’s saved as a permanent DTC so I can’t clear it. I reflashed the stock tune again and the issue is still there.

VCDS elaborates further and says 01-Engine - Status: Sporadic communication error 1000

Aside from seeing the code when I plug in, nothing else seems amiss. Any idea what the issue might be?

[MiCasa_2Casa]

Read through this thread but it sounds like the ECM Relay took care of this owner's problem:

https://www.a5oc.com/threads/car-die...0-code.167780/

I'm sure other's will post more/better/personal results.

[keithk831]

Read through this thread but it sounds like the ECM Relay took care of this owner's problem:

https://www.a5oc.com/threads/car-die...0-code.167780/

I'm sure other's will post more/better/personal results.

Thanks for the reply. Yesterday I went in and did another auto scan using VCDS, then cleared all codes from all modules and re-ran the auto scan. No codes reappeared right away. I then checked for permanent DTCs in OBD2 functions and the U0100 code was still there.

I drove around for about 10 mins and checked again, and the DTC was gone. I haven’t done much driving since, but I think this solved my issue. We’ll see what happens over the next few days.

[Theiceman]

You always get strange u codes after flashing. Just delete them and move on. They should not trip a cel.

Sent from my SM-G973W using Audizine Forum mobile app

[MiCasa_2Casa]

You always get strange u codes after flashing. Just delete them and move on. They should not trip a cel.

Sent from my SM-G973W using Audizine Forum mobile app

Yeah, unfortunately with any auto manufacturer, you get codes, when you flash your ecu.

- - - Updated - - -

Thanks for the reply. Yesterday I went in and did another auto scan using VCDS, then cleared all codes from all modules and re-ran the auto scan. No codes reappeared right away. I then checked for permanent DTCs in OBD2 functions and the U0100 code was still there.

I drove around for about 10 mins and checked again, and the DTC was gone. I haven’t done much driving since, but I think this solved my issue. We’ll see what happens over the next few days.

No worries, glad it hasn't(Or won't come back).

[kringtan]

The U0100 code and communication error you're experiencing after flashing your car back to stock could be caused by a few different issues. t's possible that the stock tune is not compatible with all of the modules and sensors in the vehicle, which could cause a communication issue. Check the software and modules to ensure that they are compatible with each other. If you're unable to diagnose and resolve the issue on your own, it may be best to take the vehicle to a professional mechanic or dealer for further diagnosis and repair.
​​​​​​https://dtcvehicles.com/

[Theiceman]

The U0100 code and communication error you're experiencing after flashing your car back to stock could be caused by a few different issues. t's possible that the stock tune is not compatible with all of the modules and sensors in the vehicle, which could cause a communication issue. Check the software and modules to ensure that they are compatible with each other. If you're unable to diagnose and resolve the issue on your own, it may be best to take the vehicle to a professional mechanic or dealer for further diagnosis and repair.
​​​​​​https://dtcvehicles.com/

thats was so captain obvious and on a first post with a link .. it just has to be spam.