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Tesla UMC_w004

Unable to charge with Mobile Connector Voltage too high / Try a different wall outlet

Common search variants: UMCw004 · UMC-w004 · UMC w004 · Search ignores case and common separators.

DriveNot yet established by verified evidence. The supplied record lists safe-to-drive status as unknown.
ChargeNot yet established by verified evidence. The supplied record lists safe-to-charge status as unknown. Verified documentation states that the vehicle cannot charge or charging may be interrupted when this alert is present.
ServiceNot yet established by verified evidence. The supplied evidence does not state when Tesla service is required for UMC_w004.
Confidence95%

Quick answer

UMC_w004 means the vehicle cannot charge, or charging was interrupted, because the Mobile Connector detected wall-outlet voltage that was too high or an unexpected increase in supply voltage. Try a different wall outlet.

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 UMC_w004 mean?

UMC_w004 means the vehicle cannot charge, or charging was interrupted, because the Mobile Connector detected wall-outlet voltage that was too high or an unexpected increase in supply voltage. Try a different wall outlet.

2. Technical explanation

Tesla documentation submitted to NHTSA states that this alert is set when the Mobile Connector detects either wall-outlet voltage that is too high or an unexpected rise in outlet supply voltage. The alert concerns charging through the Mobile Connector.

3. What system is affected?

Mobile Connector and the wall-outlet supply voltage used for charging.

4. How serious is this code?

Not yet established by verified evidence. The supplied record lists severity as unknown.

5. Symptoms you may notice

  • The vehicle cannot charge.
  • Charging is interrupted.
  • The UMC_w004 alert is displayed: “Unable to charge with Mobile Connector Voltage too high / Try a different wall outlet.”

6. Possible causes

  • The Mobile Connector detects that wall-outlet voltage is too high.
  • The Mobile Connector detects an unexpected increase in supply voltage from the wall outlet.

7. Can I still drive the vehicle?

Not yet established by verified evidence. The supplied record lists safe-to-drive status as unknown.

8. Can I charge the vehicle?

Not yet established by verified evidence. The supplied record lists safe-to-charge status as unknown. Verified documentation states that the vehicle cannot charge or charging may be interrupted when this alert is present.

9. What you can safely do

  • Try charging with a different wall outlet.
  • For Mobile Connector status-light and charging-issue troubleshooting, refer to the product owner’s manual.
  • Tesla documentation identifies Tesla Supercharger and Destination Charging locations as charging alternatives; these can be located through the vehicle touchscreen map.

10. Step-by-step troubleshooting

  1. Try charging from a different wall outlet.
  2. Consult the Mobile Connector section of the applicable Tesla owner’s manual for status-light and charging troubleshooting.

11. When to contact service

Not yet established by verified evidence. The supplied evidence does not state when Tesla service is required for UMC_w004.

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

15. Related TSBs / service bulletins

  • NHTSA Manufacturer Communication PDF 10250483: ManualC, published December 1, 2023. It documents UMC_w004 and states that the Mobile Connector detected excessive outlet voltage or an unexpected supply-voltage increase. https://static.nhtsa.gov/odi/tsbs/2023/MC-10250483-9999.pdf
  • NHTSA Manufacturer Communication PDF 10250482: ManualB, published December 1, 2023. https://static.nhtsa.gov/odi/tsbs/2023/MC-10250482-9999.pdf
  • NHTSA Manufacturer Communication PDF 10238120: Manual-2, published May 22, 2023. https://static.nhtsa.gov/odi/tsbs/2023/MC-10238120-9999.pdf
  • NHTSA Manufacturer Communication PDF 10253660: Index381, published March 26, 2024. https://static.nhtsa.gov/odi/tsbs/2024/MC-10253660-9999.pdf

16. Recall information

  • Not yet established by verified evidence.

17. Official manufacturer information

Verified NHTSA-hosted Tesla owner-documentation communications support this page. The supplied applicability data covers US Tesla Model 3 (2017–2023), Model S (2012–2023), and Model X (2016–2023).

19. Frequently asked questions

What does Tesla alert UMC_w004 mean?

It means the vehicle cannot charge, or charging is interrupted, because the Mobile Connector detected wall-outlet voltage that was too high or an unexpected increase in supply voltage from the outlet.

What should I do when UMC_w004 appears?

Tesla documentation says to try charging with a different wall outlet. It also directs users to the product owner’s manual for Mobile Connector status-light and charging troubleshooting.

Does UMC_w004 prove that the vehicle needs service?

Not yet established by verified evidence. The supplied record lists service-required status as unknown.

Can I still drive with UMC_w004?

Not yet established by verified evidence. The supplied record lists safe-to-drive status as unknown.

20. Sources & verification

Verified
Show all 24 verified sources
Tesla UMC_w004: Unable to charge with Mobile Connector Voltage too… | EV Diagnostics