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Tesla UMC_a008

Unable to charge - Wall plug temperature high Wall outlet and wiring inspection recommended

Common search variants: UMCa008 · UMC-a008 · UMC a008 · Search ignores case and common separators.

DriveNot yet established by verified evidence.
ChargeThe affected Mobile Connector charging session has stopped. Whether charging is safe by another method is not explicitly established by the diagnostic record; Tesla documentation referenced in the evidence mentions Tesla Supercharger or Destination Charging locations as charging options.
ServiceContact a qualified electrical professional for the recommended wall-outlet and wiring inspection. Tesla service requirements are not established by the supplied evidence.
Confidence95%

Quick answer

UMC_a008 means the Tesla Mobile Connector detected high temperature at the wall outlet/plug area and stopped charging to protect the outlet. Tesla documentation states this does not indicate an issue with the vehicle or Mobile Connector; it recommends wall-outlet and wiring inspection.

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1. What does UMC_a008 mean?

UMC_a008 means the Tesla Mobile Connector detected high temperature at the wall outlet/plug area and stopped charging to protect the outlet. Tesla documentation states this does not indicate an issue with the vehicle or Mobile Connector; it recommends wall-outlet and wiring inspection.

2. Technical explanation

Verified Tesla owner-manual content filed with NHTSA describes UMC_a008 as: “Unable to charge - Wall plug temperature high. Wall outlet and wiring inspection recommended.” The Mobile Connector detected that the outlet used for charging was becoming too warm, and charging stopped to protect that outlet. The verified evidence states this does not indicate an issue with the Mobile Connector or vehicle.

3. What system is affected?

AC charging supply connection: the wall outlet/plug and associated wiring used with the Tesla Mobile Connector.

4. How serious is this code?

Severity is not specified in the verified diagnostic record. Charging has stopped because high temperature was detected at the outlet/plug area.

5. Symptoms you may notice

  • UMC_a008 alert: “Unable to charge - Wall plug temperature high.”
  • Charging stops.
  • A recommendation for wall-outlet and wiring inspection is displayed.

6. Possible causes

  • The wall outlet used to charge is becoming too warm.
  • The evidence recommends inspection of the wall outlet and wiring; a specific underlying wiring or outlet defect is not established by the supplied evidence.

7. Can I still drive the vehicle?

Not yet established by verified evidence.

8. Can I charge the vehicle?

The affected Mobile Connector charging session has stopped. Whether charging is safe by another method is not explicitly established by the diagnostic record; Tesla documentation referenced in the evidence mentions Tesla Supercharger or Destination Charging locations as charging options.

9. What you can safely do

  • Do not attempt to resume charging through the outlet that triggered the high-temperature alert until the wall outlet and wiring have been inspected.
  • Arrange inspection of the wall outlet and wiring as the alert recommends.
  • Refer to the Tesla Mobile Connector owner’s manual for Mobile Connector status-light and charging-issue troubleshooting.

10. Step-by-step troubleshooting

  1. Confirm the displayed alert is UMC_a008.
  2. Use the Tesla Mobile Connector owner’s manual for the applicable product’s status-light and charging-issue guidance.
  3. Have the wall outlet and its wiring inspected. No do-it-yourself electrical repair procedure is established by the supplied evidence.

11. When to contact service

Contact a qualified electrical professional for the recommended wall-outlet and wiring inspection. Tesla service requirements are not established by the supplied evidence.

12. What the service center may check

  • Inspect the wall outlet and wiring, as recommended by the UMC_a008 alert.
  • No further inspection or diagnostic procedure is established by the supplied evidence.

13. Possible repair or resolution

  • Repair outcome is not established by verified evidence. The supplied documentation only recommends wall-outlet and wiring inspection.

14. Affected vehicles

15. Related TSBs / service bulletins

  • NHTSA Manufacturer Communication PDF 10253666 (published 2024-03-27): https://static.nhtsa.gov/odi/tsbs/2024/MC-10253666-9999.pdf
  • NHTSA Manufacturer Communication PDF 10250484 (published 2023-12-01): https://static.nhtsa.gov/odi/tsbs/2023/MC-10250484-9999.pdf
  • NHTSA Manufacturer Communication PDF 10250485 (published 2023-12-01): https://static.nhtsa.gov/odi/tsbs/2023/MC-10250485-9999.pdf

16. Recall information

  • Not yet established by verified evidence.

17. Official manufacturer information

Official NHTSA-hosted Tesla manufacturer communications document UMC_a008 and state that a high temperature was detected by the Mobile Connector at the outlet used for charging; charging stopped to protect the outlet. Example: https://static.nhtsa.gov/odi/tsbs/2024/MC-10253666-9999.pdf

19. Frequently asked questions

What does Tesla alert UMC_a008 mean?

It means the Mobile Connector detected high temperature at the wall plug/outlet area, and charging stopped to protect the outlet.

Does UMC_a008 mean the vehicle or Mobile Connector is faulty?

Tesla documentation states that this alert does not indicate an issue with the Mobile Connector or vehicle.

What inspection does Tesla recommend?

The alert recommends inspection of the wall outlet and wiring.

Which vehicles are covered by the supplied applicability data?

US Tesla Model 3 (2013–2024 across supplied entries), Model S (2012–2024), Model X (2016–2024), and Model Y (2020–2024). Exact applicability depends on the individual supplied entry.

20. Sources & verification

Accepted ResearchVerified
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