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Audi U122C00

Ethernet databus branch 1 no communication

DriveNot yet established by verified evidence.
ChargeNot yet established by verified evidence.
ServiceContact an Audi dealer or qualified Audi service provider for VIN-specific diagnosis and applicability confirmation.
Confidence95%

Quick answer

For certain 2019–2020 US Audi A8 and e-tron vehicles, U122C00 can be stored in the Gateway (J533) when the emergency call module and communication unit (ConBox, J949) temporarily stops communicating with the vehicle due to a sporadic startup issue.

This page separates verified manufacturer/regulator evidence from supporting material. Unsupported causes, repairs or safety conclusions are not guessed.

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1. What does U122C00 mean?

For certain 2019–2020 US Audi A8 and e-tron vehicles, U122C00 can be stored in the Gateway (J533) when the emergency call module and communication unit (ConBox, J949) temporarily stops communicating with the vehicle due to a sporadic startup issue.

2. Technical explanation

U122C00 means “Ethernet databus branch 1 no communication.” Audi service communications identify this DTC as one that may be stored in the data bus on-board diagnostic interface (Gateway), J533, address word 0019. The documented technical background is a startup issue that can sporadically cause the emergency call module and communication unit (ConBox), J949, address word 0075, to temporarily stop communicating with the rest of the vehicle.

3. What system is affected?

Ethernet databus communication involving the Gateway J533 and emergency call module/communication unit (ConBox) J949.

4. How serious is this code?

Unknown. Verified evidence does not establish a severity classification for this DTC.

5. Symptoms you may notice

  • U122C00 may be stored in Gateway J533.
  • The emergency call module and communication unit (ConBox) J949 may temporarily stop communicating with the rest of the vehicle.
  • The supplied Audi service evidence refers to information displayed in the instrument cluster, but the exact message or warning is not established by the supplied evidence.

6. Possible causes

  • For the applicable Audi vehicles in the cited service communications, a sporadic startup issue can temporarily interrupt communication from ConBox J949 with the rest of the vehicle.

7. Can I still drive the vehicle?

Not yet established by verified evidence.

8. Can I charge the vehicle?

Not yet established by verified evidence.

9. What you can safely do

  • Arrange diagnosis by an Audi service provider or qualified technician if the DTC is present or communication-related warnings occur.
  • Do not attempt high-voltage or module repair procedures based on this information.

10. Step-by-step troubleshooting

  1. Confirm whether U122C00 is stored in the Gateway J533, address word 0019.
  2. Have a qualified technician assess whether the DTC is sporadic and whether the condition matches Audi’s documented ConBox J949 startup communication issue.
  3. Check applicable Audi service information by VIN and vehicle configuration.

11. When to contact service

Contact an Audi dealer or qualified Audi service provider for VIN-specific diagnosis and applicability confirmation.

12. What the service center may check

  • Retrieve and document faults from Gateway J533, address word 0019.
  • Assess communication with the emergency call module and communication unit, ConBox J949, address word 0075.
  • Determine whether the stored DTC is sporadic, as described in the Audi service communications.
  • Review the applicable Audi technical service bulletin and current service instructions for the vehicle VIN.

13. Possible repair or resolution

  • Audi’s cited service communications describe a production solution of new ConBox systems in model year 2021.
  • The supplied evidence does not establish a specific repair, replacement requirement, or software action for every affected vehicle.

14. Affected vehicles

15. Related TSBs / service bulletins

  • Audi/NHTSA manufacturer communication MC-10191043, published April 20, 2021: documents U122C00 in Gateway J533 in connection with a sporadic ConBox J949 startup communication issue.
  • Audi/NHTSA manufacturer communication MC-10222110, published September 23, 2022: documents the same condition and states that new ConBox systems were introduced in MY2021.
  • Audi/NHTSA manufacturer communication MC-10226968, published November 4, 2022: documents U122C00 in Gateway J533 in connection with the ConBox J949 startup communication issue.

16. Recall information

  • No recall is established by the supplied verified evidence.

17. Official manufacturer information

Official NHTSA-hosted Audi manufacturer communications: MC-10191043, MC-10222110, and MC-10226968.

19. Frequently asked questions

What does U122C00 mean?

It means “Ethernet databus branch 1 no communication.”

Which vehicles are supported by the supplied evidence?

2019–2020 Audi A8 and 2019–2020 Audi e-tron vehicles in the US.

What documented condition can set this code?

Audi documents that a sporadic startup issue can temporarily cause ConBox J949 to stop communicating with the rest of the vehicle.

Is it safe to drive or charge?

Not yet established by verified evidence.

20. Sources & verification

Verified
Audi U122C00: Ethernet databus branch 1 no communication | EV Diagnostics