EV Diagnostics
Verified EV diagnostic knowledge page

Tesla UMC_a001

Unable to charge with Mobile Connector Inadequate outlet grounding - Try another outlet

Common search variants: UMCa001 · UMC-a001 · UMC a001 · Search ignores case and common separators.

DriveNot yet established by verified evidence.
ChargeThe alert states that charging with the Mobile Connector is unavailable at the affected outlet. Tesla directs the user to try another outlet.
ServiceTesla documentation states that this alert does not indicate a Mobile Connector or vehicle issue. Service requirements are not otherwise established by verified evidence.
Confidence95%

Quick answer

UMC_a001 means the Tesla Mobile Connector detected insufficient grounding at the electrical outlet. Tesla’s documentation says to try another outlet.

This page separates verified manufacturer/regulator evidence from supporting material. Unsupported causes, repairs or safety conclusions are not guessed.

Video guides

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 UMC_a001 mean?

UMC_a001 means the Tesla Mobile Connector detected insufficient grounding at the electrical outlet. Tesla’s documentation says to try another outlet.

2. Technical explanation

Tesla documentation submitted to NHTSA states that the Mobile Connector detected insufficient outlet grounding, likely due to an inadequate or missing ground connection. The documentation states this alert does not indicate an issue with the Mobile Connector or vehicle; it points to the outlet’s electrical grounding.

3. What system is affected?

External electrical outlet grounding used with the Tesla Mobile Connector.

4. How serious is this code?

Not yet established by verified evidence.

5. Symptoms you may notice

  • The vehicle displays UMC_a001: “Unable to charge with Mobile Connector Inadequate outlet grounding - Try another outlet.”
  • Charging with the Mobile Connector is unavailable at the affected outlet.

6. Possible causes

  • The electrical outlet has insufficient grounding.
  • An inadequate ground connection at the outlet.
  • A missing ground connection at the outlet.

7. Can I still drive the vehicle?

Not yet established by verified evidence.

8. Can I charge the vehicle?

The alert states that charging with the Mobile Connector is unavailable at the affected outlet. Tesla directs the user to try another outlet.

9. What you can safely do

  • Try another electrical outlet, as directed by the alert.
  • Do not treat this alert as evidence of a fault in the Mobile Connector or vehicle; Tesla documentation attributes it to the outlet grounding condition.
  • Have the outlet’s grounding assessed by an appropriately qualified electrical professional if necessary. Further electrical repair guidance is not established by the supplied verified evidence.

10. Step-by-step troubleshooting

  1. Connect the Mobile Connector to another outlet and check whether charging can proceed.
  2. If the condition remains after using another outlet, further troubleshooting steps are not yet established by verified evidence.

11. When to contact service

Tesla documentation states that this alert does not indicate a Mobile Connector or vehicle issue. Service requirements are not otherwise established by verified evidence.

12. What the service center may check

  • Verify the grounding condition of the electrical outlet supplying the Mobile Connector. Specific service procedures are not established by the supplied verified evidence.

13. Possible repair or resolution

  • Use an outlet with adequate grounding. Any required outlet correction must be determined by an appropriately qualified electrical professional; the exact repair is not established by verified evidence.

14. Affected vehicles

15. Related TSBs / service bulletins

  • NHTSA manufacturer communications containing Tesla owner documentation describe UMC_a001, including NHTSA document 10250480 (published December 1, 2023): https://static.nhtsa.gov/odi/tsbs/2023/MC-10250480-9999.pdf
  • Additional NHTSA-hosted Tesla documentation includes document 10253666 (published March 27, 2024): https://static.nhtsa.gov/odi/tsbs/2024/MC-10253666-9999.pdf

16. Recall information

  • Not yet established by verified evidence.

17. Official manufacturer information

Verified NHTSA-hosted Tesla documentation: https://static.nhtsa.gov/odi/tsbs/2023/MC-10250480-9999.pdf. Verified applicability records list US Tesla Model 3 (2013–2024), Model S (2012–2024), Model X (2016–2024), and Model Y (2020–2024), with overlapping year records in the supplied data.

19. Frequently asked questions

What does Tesla alert UMC_a001 mean?

It means the Mobile Connector detected insufficient grounding at the electrical outlet, likely from an inadequate or missing ground connection.

Does UMC_a001 mean the Tesla vehicle or Mobile Connector is faulty?

Tesla documentation says this alert does not indicate an issue with the Mobile Connector or vehicle; it points to the outlet grounding.

What should I do when UMC_a001 appears?

Try another electrical outlet, as the alert directs.

Is this alert applicable to my Tesla?

Supplied verified applicability records cover US Model 3, Model S, Model X, and Model Y across the listed model-year ranges. Confirm the exact vehicle configuration with Tesla documentation.

20. Sources & verification

Accepted ResearchVerified
Show all 58 verified sources
Tesla UMC_a001: Unable to charge with Mobile Connector Inadequate… | EV Diagnostics