What it means
Mitsubishi's thermistor TH2. It counts as faulty at 90°C or more (short) or -40°C or less (open), and the unit pauses for 3 minutes first. Mitsubishi notes a refrigerant circuit fault can also push this reading to extremes. With a wireless remote, the self-check reports it as 2 beeps and 2 flashes, the same as P9.
What to check, in order
- Write down the code
Note the code and unit number, as Mitsubishi's operation manual asks.
- Switch off and on once
Turn the system off at the breaker or isolator and back on. If P2 returns, leave it off and book a repair.
When to call an engineer
Call an air conditioning engineer (UK) or HVAC technician (US). Mitsubishi lists a faulty sensor, a poor contact at its connector, a broken sensor wire, a refrigerant circuit fault that makes the pipe extremely hot or cold, or a faulty indoor control board.
A repair visit will usually check the sensor's reading and its wiring.
- Note the model and serial number. They're on a label on the side of the indoor unit, and on the outdoor unit.
- Write down the exact code, and what the appliance was doing when it appeared.
- Check whether it's still under warranty. If it is, the repair may cost you nothing.
Quick answers
What does the Mitsubishi P2 error code mean?
The sensor on the indoor unit's liquid refrigerant pipe is reading as short-circuited or disconnected. Mitsubishi's thermistor TH2. It counts as faulty at 90°C or more (short) or -40°C or less (open), and the unit pauses for 3 minutes first. Mitsubishi notes a refrigerant circuit fault can also push this reading to extremes. With a wireless remote, the self-check reports it as 2 beeps and 2 flashes, the same as P9.
Can I fix Mitsubishi P2 myself?
Engineer only (engineer visit). Start with: write down the code; switch off and on once. Call an air conditioning engineer (UK) or HVAC technician (US). Mitsubishi lists a faulty sensor, a poor contact at its connector, a broken sensor wire, a refrigerant circuit fault that makes the pipe extremely hot or cold, or a faulty indoor control board.
Is Mitsubishi P2 worth repairing?
Worth fixing. Most of the causes Mitsubishi lists are sensor or wiring repairs. The engineer should also rule out a refrigerant circuit problem, which is on the same list.
Checked against
- Mitsubishi Electric SLZ-KF09/12/15/18NA1 ceiling cassette (M-series) Technical & Service Manual TCH118A (PDF)
- Mitsubishi Electric SLZ-M15-60FA ceiling cassette Technical & Service Manual OCH522 (PDF)
- Mitsubishi Electric SEZ-KD09/12/15/18NA(4) ducted (M-series) Technical & Service Manual HWE0802B (PDF)
- Mitsubishi Electric PCA-M35-140KA indoor unit Service Manual OCH659 (PDF)
Last reviewed October 2026. Manufacturers update their pages, and your manual is the final word. Spotted a mistake? Email contact@appliance-error-codes.com.