UMC family
UMC_a004_inputOverVoltage
Unable to charge with Mobile Connector
What does the UMC_a004_inputOverVoltage alert mean?
UMC AC input voltage exceeded upper limit
What you'll see in your Tesla
- Unable to charge with Mobile Connector
- Voltage too high / Try a different wall outlet
What triggers it
UMC input voltage has risen above 300 V RMS
When it clears
UMC input voltage has fallen below 300 V RMS
Potential impact
UMC will not allow charging until AC input voltage is within 90-300 V RMS
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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Alerts like this reach MyTeslaMate through your car's Tesla telemetry API. MyTeslaMate logs every alert your Tesla reports and turns it into readable history and real-time notifications — hosted TeslaMate with no server to run.