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Audi B157811

Hall sensor for roof blind motor supply, short circuit to ground

DriveNot yet established by verified evidence.
ChargeNot yet established by verified evidence.
ServiceService is appropriate if B157811 is stored or if the roof blind cannot complete basic settings. The verified communication specifically addresses diagnostic handling before motor replacement.
Confidence95%

Quick answer

For certain 2020–2021 Audi A8 vehicles in the US, DTC B157811 means: “Hall sensor for roof blind motor supply, short circuit to ground.” An Audi/NHTSA service communication says to attempt basic settings on the relevant roof drive motor before condemning or replacing the sunroof glass panel drive motor V1 or sunroof shade drive motor V260.

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 B157811 mean?

For certain 2020–2021 Audi A8 vehicles in the US, DTC B157811 means: “Hall sensor for roof blind motor supply, short circuit to ground.” An Audi/NHTSA service communication says to attempt basic settings on the relevant roof drive motor before condemning or replacing the sunroof glass panel drive motor V1 or sunroof shade drive motor V260.

2. Technical explanation

Verified evidence identifies B157811 as a roof-blind motor Hall-sensor supply fault described as a short circuit to ground. The cited Audi service communication lists this DTC in a scenario involving roof-blind basic-setting concerns and revised sunroof voltage-control parameters in production.

3. What system is affected?

Roof blind / sunroof shade drive system, including the Hall sensor supply for the roof blind motor.

4. How serious is this code?

Not yet established by verified evidence.

5. Symptoms you may notice

  • The service communication associates B157811 with a roof-blind scenario involving a “Roof blind, no basic setting” DTC (B154454).
  • Other customer-visible symptoms are not yet established by verified evidence.

6. Possible causes

  • The verified DTC definition identifies a short circuit to ground in the Hall sensor supply for the roof blind motor.
  • The specific failed component, wiring location, or underlying root cause is not yet established by verified evidence.

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

  • Have the fault evaluated by an Audi-qualified service facility.
  • Provide the stored DTC B157811 and ask the service facility to review the cited Audi/NHTSA manufacturer communication.
  • Do not replace the sunroof glass panel drive motor V1 or sunroof shade drive motor V260 solely based on this code before the applicable basic-setting attempt described in the service communication.

10. Step-by-step troubleshooting

  1. The Audi service communication instructs technicians to attempt to set the basic settings on either drive motor before condemning and replacing sunroof glass panel drive motor V1 or sunroof shade drive motor V260.
  2. Further diagnostic steps are not established by the supplied verified evidence.

11. When to contact service

Service is appropriate if B157811 is stored or if the roof blind cannot complete basic settings. The verified communication specifically addresses diagnostic handling before motor replacement.

12. What the service center may check

  • Confirm DTC B157811: Hall sensor for roof blind motor supply, short circuit to ground.
  • Where applicable, assess the roof-blind basic-setting condition referenced by the service communication.
  • Attempt basic settings on the relevant drive motor before condemning or replacing V1 or V260.

13. Possible repair or resolution

  • The verified communication states that sunroof voltage-control parameters were changed in production.
  • A vehicle-specific repair outcome is not established by verified evidence.
  • The supplied evidence does not establish that replacement of V1 or V260 is required for every occurrence of B157811.

14. Affected vehicles

15. Related TSBs / service bulletins

  • NHTSA Manufacturer Communication PDF 10189651: A6021522054505_3, published March 26, 2021. It lists B157811 under a roof-blind basic-setting scenario and directs a basic-settings attempt before condemning or replacing the listed drive motors.
  • Source: https://static.nhtsa.gov/odi/tsbs/2021/MC-10189651-0001.pdf

16. Recall information

  • No recall information was supplied in the verified evidence.

17. Official manufacturer information

Verified applicability: Audi A8, model years 2020–2021, US region. Source: NHTSA Manufacturer Communication PDF 10189651, Audi communication A6021522054505_3, published March 26, 2021.

19. Frequently asked questions

What does Audi code B157811 mean?

It means “Hall sensor for roof blind motor supply, short circuit to ground.”

Which vehicles are supported by the supplied evidence?

The supplied applicability evidence covers US-market 2020–2021 Audi A8 vehicles.

Should the roof drive motor be replaced immediately?

The cited Audi service communication says to attempt basic settings on either drive motor before condemning and replacing the sunroof glass panel drive motor V1 or sunroof shade drive motor V260.

Is it safe to drive or charge with B157811?

Not yet established by verified evidence.

20. Sources & verification

Verified
Audi B157811: Hall sensor for roof blind motor supply, short circuit… | EV Diagnostics