u2
Moderate
Mitsubishi Electric · Mini-Splits & Ductless Systems
Low Voltage / High Current Abnormality
Quick Answer
Error code U2 on your Mitsubishi Electric Mini-Splits & Ductless Systems means: Low Voltage / High Current Abnormality. This is usually fixable — see the step-by-step guide below.
Likely Causes
  1. Supply voltage to the outdoor unit below minimum operating threshold
  2. Undersized circuit wiring causing excessive voltage drop under load
  3. Loose connection at the electrical disconnect or terminal block
  4. Utility voltage sag during high-demand periods
How to Fix It
1
Measure voltage at the outdoor unit disconnect under operating load conditions
2
Verify voltage stays within the unit's rated range (typically 187-253VAC for 230V models)
3
Check all terminal connections and the disconnect switch for tight connections
4
Verify the circuit wire gauge is adequate for the distance and amperage load
5
If voltage is consistently low, a licensed electrician should evaluate the electrical supply
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Disconnect switch (if contacts are worn)
Electrical wire (correct gauge)
Wire connectors
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