CostolioMitsubishi Electric Mr. SLIM (PLY / PEY / PCY), Singapore list (-SG models) error codes
11 heat pump / mini-split error codes for Mitsubishi Electric Mr. SLIM (PLY / PEY / PCY), Singapore list (-SG models), what each one means and what to try, paraphrased from Mitsubishi Electric's own source. Codes vary by model, so confirm in your own manual.
All codes
- P1 Intake sensor error.
- P2 / P9 Pipe (TH2) or pipe (TH5) sensor error.
- E6 / E7 Indoor-outdoor communication error.
- P4 Drain float switch connector open.
- P6 Freeze protection (cooling) or overheat protection (heating) operated.
- P8 Pipe temperature error.
- PL Refrigerant circuit abnormal.
- U2 High discharge temperature or not enough refrigerant.
- UP Compressor overcurrent interruption.
- UF Compressor overcurrent because the compressor is locked.
- U1 / Ud Abnormal high pressure or overheat protection.
P1
What it means: Intake sensor error. This one often needs a licensed technician.
What to try
- Call a Mitsubishi Electric service technician.
P2 / P9
What it means: Pipe (TH2) or pipe (TH5) sensor error. This one often needs a licensed technician.
What to try
- Call a Mitsubishi Electric service technician.
E6 / E7
What it means: Indoor-outdoor communication error. This one often needs a licensed technician.
What to try
- Call a Mitsubishi Electric service technician.
P4
What it means: Drain float switch connector open. This one often needs a licensed technician.
What to try
- Call a Mitsubishi Electric service technician.
P6
What it means: Freeze protection (cooling) or overheat protection (heating) operated. This one often needs a licensed technician.
What to try
- Call a Mitsubishi Electric service technician.
P8
What it means: Pipe temperature error. This one often needs a licensed technician.
What to try
- Call a Mitsubishi Electric service technician.
PL
What it means: Refrigerant circuit abnormal. This one often needs a licensed technician.
What to try
- Call a Mitsubishi Electric service technician.
U2
What it means: High discharge temperature or not enough refrigerant. This one often needs a licensed technician.
What to try
- Call a Mitsubishi Electric service technician.
UP
What it means: Compressor overcurrent interruption. This one often needs a licensed technician.
What to try
- Call a Mitsubishi Electric service technician.
UF
What it means: Compressor overcurrent because the compressor is locked. This one often needs a licensed technician.
What to try
- Call a Mitsubishi Electric service technician.
U1 / Ud
What it means: Abnormal high pressure or overheat protection. This one often needs a licensed technician.
What to try
- Call a Mitsubishi Electric service technician.
Source
- Mr. SLIM error codes, PLY/PEY/PCY (Mitsubishi Electric Singapore) (checked 2026-11-02)
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