Audi P0AA400
Hybrid/EV Battery Negative Contactor Circuit Stuck Closed
Quick answer
P0AA400 means “Hybrid/EV Battery Negative Contactor Circuit Stuck Closed.” Verified applicability is the 2022 Audi e-tron GT in the US.
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 P0AA400 mean?
P0AA400 means “Hybrid/EV Battery Negative Contactor Circuit Stuck Closed.” Verified applicability is the 2022 Audi e-tron GT in the US.
2. Technical explanation
A verified Audi Technical Service Bulletin lists P0AA400 as “Hybrid/EV Battery Negative Contactor Circuit Stuck Closed.” The supplied evidence does not establish diagnostic steps, root cause, repair procedure, driving or charging status, or safety instructions for this code.
3. What system is affected?
Hybrid/EV battery negative contactor circuit.
4. How serious is this code?
Not yet established by verified evidence.
5. Symptoms you may notice
- Not yet established by verified evidence.
6. Possible causes
- 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
- Do not attempt high-voltage battery or contactor repair based on this information.
- Seek diagnosis by an appropriately qualified Audi service provider; the need for service is not otherwise established by the supplied evidence.
10. Step-by-step troubleshooting
- Not yet established by verified evidence.
11. When to contact service
Not yet established by verified evidence. The supplied official Audi bulletin identifies this DTC but the provided evidence does not state a required customer action or repair process.
12. What the service center may check
- Not yet established by verified evidence.
13. Possible repair or resolution
- Not yet established by verified evidence.
14. Affected vehicles
- Audi e-tron GT · 2022 · US
15. Related TSBs / service bulletins
- Audi Technical Service Bulletin / NHTSA Manufacturer Communication PDF 10205971, titled “A9321602065473_1,” published December 22, 2021, lists P0AA400 as “Hybrid/EV Battery Negative Contactor Circuit Stuck Closed.”
- The supplied bulletin evidence also lists P0AA400 among several hybrid/high-voltage battery controller and battery contactor DTCs.
16. Recall information
- Not yet established by verified evidence.
17. Official manufacturer information
Verified source: NHTSA Manufacturer Communication PDF 10205971 (Audi), published 2021-12-22: https://static.nhtsa.gov/odi/tsbs/2021/MC-10205971-0001.pdf
19. Frequently asked questions
What does P0AA400 mean on an Audi e-tron GT?
It means “Hybrid/EV Battery Negative Contactor Circuit Stuck Closed.”
Which vehicle is verified as applicable?
The supplied applicability record identifies the US-market 2022 Audi e-tron GT.
Can I drive or charge with P0AA400?
Not yet established by verified evidence.
Does the supplied evidence identify a repair?
No. A repair resolution is not yet established by verified evidence.