p9
Moderate
Mitsubishi Electric · Mini-Splits & Ductless Systems
Pipe Temperature Sensor 2 Fault
Quick Answer
Error code P9 on your Mitsubishi Electric Mini-Splits & Ductless Systems means: Pipe Temperature Sensor 2 Fault. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
Likely Causes
How to Fix It
1
Locate the secondary pipe thermistor on the indoor unit piping
2
Measure thermistor resistance and compare to the manufacturer's chart
3
Verify the sensor is properly mounted to the pipe with good thermal contact
4
Check the connector at the PCB and inspect wiring for damage
5
Replace the sensor if out of specification
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
Pipe thermistor (secondary)
Insulation tape
Sensor mounting clip
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