Audi B239C11
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 B239C11 is documented as “microphone 2, short circuit to ground” in the emergency call module and communication unit (J949, address 0075). Audi technical bulletins state that a software malfunction can enter this DTC erroneously. While the SOS warning is displayed, e-Call functionality remains active.
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 B239C11 mean?
For certain 2021 US Audi A7, A8, Q5, and e-tron vehicles, DTC B239C11 is documented as “microphone 2, short circuit to ground” in the emergency call module and communication unit (J949, address 0075). Audi technical bulletins state that a software malfunction can enter this DTC erroneously. While the SOS warning is displayed, e-Call functionality remains active.
2. Technical explanation
Verified Audi/NHTSA manufacturer communications associate B239C11 with microphone 2, short circuit to ground, stored in the emergency call module and communication unit J949 (address word 0075). The communications state that a software malfunction can cause B239C11, along with B129B11, to be stored erroneously. This evidence does not establish an actual microphone wiring or microphone hardware fault in every occurrence.
3. What system is affected?
Emergency call module and communication unit J949 (address word 0075), including the e-Call/SOS emergency-call function.
4. How serious is this code?
Not yet established by verified evidence.
5. Symptoms you may notice
- The instrument cluster may display: “SOS – Emergency call malfunction, please contact service.”
- DTC B239C11 may be stored in J949.
- Audi states that e-Call functionality remains active while the warning message is displayed.
6. Possible causes
- A software malfunction can cause B239C11 to be entered erroneously.
- An actual component, wiring, or microphone fault is not established by the supplied 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 support if the SOS emergency-call malfunction message is displayed.
- Do not assume the stored DTC proves a microphone hardware failure; Audi documentation identifies a possible erroneous software-related entry.
10. Step-by-step troubleshooting
- A verified Audi service instruction in the February 2021 communication is to clear the DTCs.
- The supplied evidence does not establish further diagnostic steps.
- No high-voltage diagnostic or repair action is identified in the supplied evidence.
11. When to contact service
The displayed message instructs the customer to contact service. Contact an Audi service provider for evaluation if the warning is present or returns after the DTC is cleared.
12. What the service center may check
- Check the emergency call module and communication unit J949 (address 0075) for stored DTC B239C11.
- Clear the DTCs, as specified in the February 2021 Audi manufacturer communication.
- If the condition persists, further service checks are not yet established by the supplied verified evidence.
13. Possible repair or resolution
- Clear the DTCs per the February 2021 Audi manufacturer communication.
- The November 2021 communication states that the bulletin would be updated when more information became available.
- A permanent repair, software update, or parts replacement is not established by the supplied verified evidence.
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/NHTSA Manufacturer Communication 10187352, published February 17, 2021: identifies B239C11 and B129B11 in J949, states e-Call remains active, attributes erroneous entries to a possible software malfunction, and instructs clearing the DTCs.
- Audi/NHTSA Manufacturer Communication 10203173, published November 3, 2021: identifies the same warning, DTCs, and possible software malfunction; states a solution was not yet provided and the bulletin would be updated when more information became available.
16. Recall information
- Not yet established by verified evidence.
17. Official manufacturer information
Official NHTSA-hosted Audi communications: https://static.nhtsa.gov/odi/tsbs/2021/MC-10187352-0001.pdf and https://static.nhtsa.gov/odi/tsbs/2021/MC-10203173-0001.pdf
19. Frequently asked questions
What does Audi DTC B239C11 mean?
In the supplied Audi/NHTSA communications, B239C11 is listed as microphone 2, short circuit to ground, stored in the emergency call module and communication unit J949 (address 0075).
Does the SOS warning disable e-Call?
No. The supplied Audi communications state that e-Call functionality remains active while the warning message is displayed.
Is B239C11 always a failed microphone?
No. Audi states that a software malfunction can cause the DTC to be entered erroneously. The supplied evidence does not establish a hardware failure in every case.
What Audi models are covered by the supplied evidence?
The verified applicability data identifies 2021 US Audi A7, A8, Q5, and e-tron vehicles.