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Audi U15AC00

Signal damping log Malfunction

DriveNot yet established by verified evidence.
ChargeNot yet established by verified evidence. The supplied documents discuss DC-charger communication interruptions, but do not establish charging capability or safety for every vehicle with U15AC00.
ServiceContact an Audi service facility if U15AC00 is not known to be the documented post-flash static DTC, if charging is interrupted, or if other warnings or DTCs are present.
Confidence95%

Quick answer

For certain US-market 2019–2021 Audi e-tron vehicles, U15AC00 means “Signal damping log Malfunction.” Audi documentation states that after a specified flashing procedure, U15AC00 can be stored statically due to a diagnostic flaw and cannot be erased; in that specific post-flash context, Audi says it may be ignored.

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 U15AC00 mean?

For certain US-market 2019–2021 Audi e-tron vehicles, U15AC00 means “Signal damping log Malfunction.” Audi documentation states that after a specified flashing procedure, U15AC00 can be stored statically due to a diagnostic flaw and cannot be erased; in that specific post-flash context, Audi says it may be ignored.

2. Technical explanation

Verified Audi manufacturer communications list U15AC00 as “Signal damping log Malfunction.” One official communication states that, after a flashing procedure, U15AC00 and U15BF00 may be present because of a diagnostic flaw, remain static, and cannot be erased. The same communication instructs that these DTCs may be ignored in that stated context. Other supplied communications include U15AC00 among DTCs discussed in material concerning interrupted communication between certain DC chargers and the vehicle. The supplied evidence does not establish that U15AC00 alone identifies a failed component or a single root cause.

3. What system is affected?

Not yet established by verified evidence. The supplied Audi documents associate the code with charging-related communications, including material about certain DC chargers, but do not establish a specific failed system or component for U15AC00 alone.

4. How serious is this code?

Not yet established by verified evidence.

5. Symptoms you may notice

  • A static U15AC00 may be present after the specified flashing procedure and may not erase because of a diagnostic flaw.
  • The supplied evidence does not establish additional vehicle symptoms caused by U15AC00 alone.

6. Possible causes

  • After the specified flashing procedure, Audi states U15AC00 may be present because of a diagnostic flaw and may remain static.
  • The supplied evidence discusses interrupted communication between certain DC chargers and the vehicle, but does not establish this as the cause of U15AC00 alone.
  • No component-level cause is 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. The supplied documents discuss DC-charger communication interruptions, but do not establish charging capability or safety for every vehicle with U15AC00.

9. What you can safely do

  • Record whether the code appeared following a vehicle flashing procedure.
  • If charging behavior is affected, seek assessment by an Audi service facility.
  • Do not attempt high-voltage-system repairs.

10. Step-by-step troubleshooting

  1. Have an Audi-qualified technician determine whether the code is the documented static post-flash condition.
  2. Review the vehicle’s diagnostic context, including whether the specified flashing procedure was recently performed.
  3. If DC charging communication concerns are present, have the condition evaluated using Audi service information.

11. When to contact service

Contact an Audi service facility if U15AC00 is not known to be the documented post-flash static DTC, if charging is interrupted, or if other warnings or DTCs are present.

12. What the service center may check

  • Confirm whether the vehicle received the applicable flashing procedure.
  • Check whether U15AC00 is static and accompanied by U15BF00, as described in Audi’s communication.
  • Assess charging-related diagnostic context, including any DC-charger communication concern.
  • Follow applicable Audi service information; the supplied evidence does not provide a component-repair procedure.

13. Possible repair or resolution

  • For the specific post-flash diagnostic-flaw condition described by Audi, U15AC00 may be ignored even though it is static and cannot be erased.
  • Not yet established by verified evidence for U15AC00 outside that specific context.

14. Affected vehicles

15. Related TSBs / service bulletins

  • NHTSA Manufacturer Communication 10191575, published April 30, 2021: states that U15AC00 may be static and non-erasable after a flashing procedure because of a diagnostic flaw; Audi says it may be ignored in that context. https://static.nhtsa.gov/odi/tsbs/2021/MC-10191575-0001.pdf
  • NHTSA Manufacturer Communication 10191572, published April 30, 2021: lists U15AC00 as “Signal damping log Malfunction.” https://static.nhtsa.gov/odi/tsbs/2021/MC-10191572-0001.pdf
  • NHTSA Manufacturer Communication 10189601, published March 29, 2021: lists U15AC00 in material discussing interrupted communication between certain DC chargers and the vehicle. https://static.nhtsa.gov/odi/tsbs/2021/MC-10189601-0001.pdf
  • NHTSA Manufacturer Communication 10186996, published February 5, 2021: lists U15AC00 as “Signal damping log Malfunction.” https://static.nhtsa.gov/odi/tsbs/2021/MC-10186996-0001.pdf

16. Recall information

  • Not yet established by verified evidence.

17. Official manufacturer information

Verified applicability: Audi e-tron, US market, model years 2019–2021. Official source: NHTSA-hosted Audi manufacturer communications.

19. Frequently asked questions

What does Audi code U15AC00 mean?

The verified Audi documentation identifies U15AC00 as “Signal damping log Malfunction.”

Can U15AC00 be ignored?

Audi states it may be ignored only in the documented situation where it appears statically after the specified flashing procedure due to a diagnostic flaw and cannot be erased.

Does U15AC00 prove that a part has failed?

No. The supplied verified evidence does not establish a specific failed component or a single root cause from U15AC00 alone.

Which vehicles are verified as applicable?

The supplied applicability evidence covers US-market Audi e-tron vehicles from model years 2019 through 2021.

20. Sources & verification

Verified
Audi U15AC00: Signal damping log Malfunction | EV Diagnostics