UMC family
UMC_a040_gndDisconnected
Mobile Connector inadequately grounded
What does the UMC_a040_gndDisconnected alert mean?
Universal Mobile Connector (UMC) AC input side ground impedance exceeded warning threshold. Charging is not affected.
What you'll see in your Tesla
- Mobile Connector inadequately grounded
- Connect to grounded outlet
What triggers it
UMC AC input side ground impedance is above 1 Mohm
When it clears
UMC AC input side ground impedance has fallen below 10 kOhms
Potential impact
UMC will display a warning LED pattern, but will allow charging at the nominal current
Affected models
Cybertruck
Model 3 2017-2023
Model 3 2024+
Model S 2021+
Model X 2021+
Model Y
Model Y 2025+
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