Audi P0CA400
Hybrid/EV Battery Charging Voltage High
Quick answer
Audi DTC P0CA400 means “Hybrid/EV Battery Charging Voltage High.” Verified Audi/NHTSA bulletin evidence lists it in connection with interrupted communication at certain DC chargers, which can temporarily suspend charging and may also produce AC charging communication errors.
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 P0CA400 mean?
Audi DTC P0CA400 means “Hybrid/EV Battery Charging Voltage High.” Verified Audi/NHTSA bulletin evidence lists it in connection with interrupted communication at certain DC chargers, which can temporarily suspend charging and may also produce AC charging communication errors.
2. Technical explanation
For applicable Audi e-tron vehicles, an official manufacturer communication identifies P0CA400 among DTCs that can be stored when communication between certain DC chargers and the vehicle is interrupted. The bulletin states that this interruption can temporarily suspend charging and that the vehicle may also have AC charging communication errors. The documented production solution is updated onboard charger (OBC) software.
3. What system is affected?
Hybrid/EV battery charging and charging communications; the bulletin identifies the onboard charger (OBC) software as the production-solution area.
4. How serious is this code?
Not yet established by verified evidence.
5. Symptoms you may notice
- Charging may be temporarily suspended during use of certain DC chargers.
- AC charging communication errors may also be present.
6. Possible causes
- For applicable vehicles, the verified bulletin describes interrupted communication between certain DC chargers and the vehicle.
- Not yet established by verified evidence whether a high-voltage battery fault, charging-station fault, wiring fault, or another cause is present in an individual vehicle.
7. Can I still drive the vehicle?
Not yet established by verified evidence.
8. Can I charge the vehicle?
Charging can be temporarily suspended when the documented DC-charger communication interruption occurs. Whether charging should be continued or attempted is not yet established by verified evidence.
9. What you can safely do
- Record the charger type and circumstances if charging is temporarily suspended or communication errors occur.
- Have an Audi service provider evaluate the stored DTCs and applicable software information.
- Do not attempt high-voltage battery or charging-system repairs yourself.
10. Step-by-step troubleshooting
- Confirm whether the vehicle is a US-market 2020–2021 Audi e-tron covered by the listed applicability evidence.
- Retrieve and document stored diagnostic trouble codes.
- Check for the applicable Audi onboard charger (OBC) software update identified in the manufacturer communication.
- Not yet established by verified evidence what additional diagnostic steps are required for this code.
11. When to contact service
Contact an Audi service provider if P0CA400 is stored or charging is suspended. Ask the provider to check applicability of the Audi manufacturer communication and the updated OBC software.
12. What the service center may check
- Retrieve fault memory, including P0CA400 and any accompanying charging-related DTCs.
- Assess whether the event involved interrupted communication with a DC charger.
- Check the vehicle for the updated onboard charger (OBC) software described in the bulletin.
13. Possible repair or resolution
- The verified manufacturer communication identifies updated onboard charger (OBC) software as the production solution.
- The exact repair outcome for an individual vehicle is not yet established by verified evidence.
14. Affected vehicles
- Audi e-tron · 2020–2021 · US
- Audi e-tron · 2021 · US
15. Related TSBs / service bulletins
- NHTSA Manufacturer Communication PDF 10189601, Audi document A9321452061788_2, published March 29, 2021: Lists P0CA400 and states that certain DC chargers can have interrupted vehicle communication, temporarily suspending charging; updated OBC software is identified as the production solution. https://static.nhtsa.gov/odi/tsbs/2021/MC-10189601-0001.pdf
- NHTSA Manufacturer Communication PDF 10191572, Audi document A9321472061788_3, published April 30, 2021: Lists P0CA400 among related charging DTCs. https://static.nhtsa.gov/odi/tsbs/2021/MC-10191572-0001.pdf
16. Recall information
- Not yet established by verified evidence.
17. Official manufacturer information
Verified applicability evidence: Audi e-tron, US market, model years 2020–2021. Source: NHTSA-hosted Audi manufacturer communications 10189601 and 10191572.
19. Frequently asked questions
What does Audi P0CA400 mean?
It means “Hybrid/EV Battery Charging Voltage High.”
What does the verified Audi bulletin associate with P0CA400?
It lists P0CA400 in a set of charging-related DTCs associated with interrupted communication between certain DC chargers and the vehicle. The bulletin says charging can be temporarily suspended and AC charging communication errors may also occur.
What solution does the bulletin identify?
Updated onboard charger (OBC) software is identified as the production solution.
Which vehicles are supported by the supplied applicability evidence?
US-market 2020–2021 Audi e-tron vehicles.