Audi B129B11
While a warning message is displayed in the instrument cluster, the e-Call functionality remains active. Technical Background A software malfunction can cause the aforementioned DT
Quick answer
For certain 2021 US Audi A7, A8, Q5, and e-tron vehicles, DTC B129B11 can be stored because of a software malfunction. The instrument cluster may display “SOS – Emergency call malfunction, please contact service,” but verified Audi bulletin evidence states that e-Call functionality remains active while the warning is displayed.
This page separates verified manufacturer/regulator evidence from supporting material. Unsupported causes, repairs or safety conclusions are not guessed.
Watch Videos
Relevant videos play here without leaving this diagnostic page.
No sufficiently relevant embeddable video has been accepted for this diagnostic yet.
Videos are supporting material and never override OEM or regulator evidence.
1. What does B129B11 mean?
For certain 2021 US Audi A7, A8, Q5, and e-tron vehicles, DTC B129B11 can be stored because of a software malfunction. The instrument cluster may display “SOS – Emergency call malfunction, please contact service,” but verified Audi bulletin evidence states that e-Call functionality remains active while the warning is displayed.
2. Technical explanation
B129B11 is identified in the verified manufacturer communications as “microphone 1, short circuit to ground.” It is stored in the emergency call module and communication unit, J949, at address word 0075. Audi’s technical background states that a software malfunction can cause this DTC to be entered erroneously.
3. What system is affected?
Emergency call module and communication unit, J949 (address word 0075), including e-Call functionality.
4. How serious is this code?
Not yet established by verified evidence. The verified bulletins specifically state that e-Call functionality remains active while the warning message is displayed.
5. Symptoms you may notice
- The instrument cluster may display: “SOS – Emergency call malfunction, please contact service.”
- DTC B129B11 may be stored in J949, the emergency call module and communication unit, at address word 0075.
6. Possible causes
- A software malfunction can cause B129B11 to be entered erroneously.
- Other causes are 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
- Arrange service evaluation if the SOS emergency-call malfunction message is displayed.
- Provide the stored DTC and the instrument-cluster message to the service facility.
- Do not assume the DTC confirms a physical microphone fault; verified Audi bulletin evidence identifies a possible erroneous software-triggered entry.
10. Step-by-step troubleshooting
- Verify whether B129B11 is stored in J949 at address word 0075.
- Verify whether the instrument cluster displays “SOS – Emergency call malfunction, please contact service.”
- A service facility should assess the vehicle using the applicable Audi manufacturer guidance. Further diagnostic steps are not established by the supplied verified evidence.
11. When to contact service
Contact an Audi service facility when the SOS emergency-call malfunction message is displayed or B129B11 is stored. The supplied evidence does not establish whether immediate service is required.
12. What the service center may check
- Check J949, the emergency call module and communication unit, for stored DTC B129B11.
- Check for the associated DTC B239C11, identified by Audi as microphone 2, short circuit to ground.
- Confirm the presence of the SOS emergency-call malfunction message.
- Evaluate whether the DTC entry is associated with the software malfunction described in the applicable Audi manufacturer communication.
13. Possible repair or resolution
- The verified evidence identifies a software malfunction as a reason B129B11 can be entered erroneously.
- The supplied evidence does not establish a specific repair, software version, update procedure, or replacement requirement.
14. Affected vehicles
- Audi A7 · 2021 · US
- Audi A8 · 2021 · US
- Audi Q5 · 2021 · US
- Audi e-tron · 2021 · US
15. Related TSBs / service bulletins
- Audi manufacturer communication A9121472061625_3, published through NHTSA on November 3, 2021 (NHTSA communication MC-10203173-0001). It states that a software malfunction can cause B129B11 and B239C11 to be entered erroneously, and that e-Call remains active while the warning message is displayed.
- Audi manufacturer communication A9121672061625_2, published through NHTSA on February 17, 2021 (NHTSA communication MC-10187352-0001). It identifies the same DTCs, software-malfunction background, and continued e-Call functionality during the warning.
16. Recall information
- No recall information was supplied in the verified evidence.
17. Official manufacturer information
Verified official manufacturer communications are available from NHTSA: https://static.nhtsa.gov/odi/tsbs/2021/MC-10203173-0001.pdf and https://static.nhtsa.gov/odi/tsbs/2021/MC-10187352-0001.pdf
19. Frequently asked questions
What does Audi DTC B129B11 mean?
In the verified Audi manufacturer communications, B129B11 is identified as microphone 1, short circuit to ground, stored in J949, the emergency call module and communication unit, at address word 0075.
Does the SOS warning mean e-Call is inactive?
No. The verified Audi bulletin evidence states that e-Call functionality remains active while the warning message is displayed.
Can B129B11 be caused by software?
Yes. Audi’s verified technical background states that a software malfunction can cause the listed DTCs to be entered erroneously.
Which vehicles are covered by the supplied applicability evidence?
The supplied applicability evidence covers US-market 2021 Audi A7, A8, Q5, and e-tron vehicles.