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ErrBase

Mitsubishi Mini-Split Error Codes: Complete MSZ and MXZ Series Guide

Quick Answer

Mitsubishi mini-splits display error codes on the indoor unit display or blink the operation LED. The most common codes are E6 (indoor to outdoor communication fault), P4 (drain pan full), P5 (drain float switch), E9 (drain pump failure), P6 (CT sensor overcurrent), and P8 (freeze protection or low refrigerant).

Mitsubishi mini-splits display error codes on the indoor unit display or blink the operation LED. The most common codes are E6 (indoor to outdoor communication fault), P4 (drain pan full), P5 (drain float switch), E9 (drain pump failure), P6 (CT sensor overcurrent), and P8 (freeze protection or low refrigerant). E-series codes typically point to electrical or communication faults. P-series codes are protection faults - usually drainage or refrigerant issues.

MitsubishiMinisplit

About These Mitsubishi Minisplit Error Codes

Reference hub for all Mitsubishi MSZ and MXZ mini-split error codes. E-series codes are electrical and communication faults. P-series codes are protection trips from drainage, refrigerant, or safety sensors.

Most Common Error Codes

Indoor to outdoor unit communication loss (E6)40%
Drain pump failure (E9)24%
CT sensor fault (P6)14%
Drain float switch activated (P5)12%
Drain pan overflow (P4)10%

Symptoms You May Notice

  • Indoor unit displays an error code
  • Operation light blinking instead of steady
  • System shuts down unexpectedly
  • No heating or cooling despite system running

Tools Required for Diagnosis

FlashlightCompressed airMultimeter

How to Identify Your Error Code

1

Note the exact error code displayed on the indoor unit or use

Note the exact error code displayed on the indoor unit or use the diagnostic mode (Mode x10, then Power) to retrieve stored codes.

2

For P4 or P5 codes, check the condensate drain line

3

For E6, visually inspect the communication wire between indoor

4

For P8, check the air filter on the indoor unit

5

Power cycle the indoor unit by pressing the Power button to turn

Frequently Asked Questions

How do I retrieve a Mitsubishi mini-split error code from the remote?
Press the Mode button on the remote 10 times rapidly, then press the Power button. The indoor unit will display the stored fault code. On some models the code is shown as a number; on others it blinks the operation LED a set number of times.
What do E-codes versus P-codes mean on Mitsubishi mini-splits?
E-codes (E6, E9) typically indicate electrical or communication faults between components. P-codes (P4, P5, P6, P8) are protection faults - the system has detected a condition that could cause damage and has shut down to protect itself.
Can I reset a Mitsubishi mini-split error code myself?
Yes. Turn off the unit with the remote, then turn off the circuit breaker for 60 seconds and back on. Power the unit back on with the remote. This clears the code from active memory, but if the underlying problem remains the code will return.
My Mitsubishi mini-split shows an error but the remote does not display a code. How do I diagnose it?
If the display shows only a blinking light and no code, enter diagnostic mode (Mode x10, then Power) to force the unit to display the stored code. Alternatively, count the blink pattern - the number of blinks corresponds to the error number for many MSZ models.
How often should I service my Mitsubishi mini-split to avoid error codes?
Clean the air filter every 2 weeks in heavy-use conditions or monthly for average use. Have a licensed technician check refrigerant levels and the outdoor coil annually. Clean the condensate drain line every 6 months to prevent P4 and P5 drain codes.

Related Mitsubishi Minisplit Error Codes

Code: E6Mitsubishi Mini-Split E6 Error Code: Communication Fault Between Indoor and Outdoor UnitsCode: E9Mitsubishi Mini-Split E9 Error Code: Drain Pump MalfunctionCode: P6Mitsubishi Mini-Split P6 Error Code: Current Transformer Sensor FaultCode: P4Mitsubishi Mini-Split P4 Error Code: Drain Pan OverflowCode: P5Mitsubishi Mini-Split P5 Error Code: Drain System MalfunctionCode: P8Mitsubishi Mini-Split P8 Error Code: Freeze Protection or Low Refrigerant

Models Known to Experience HUB Errors

This repair applies to most Mitsubishi minisplits with this error code. Common model numbers include:

MSZ-GL12NA, MSZ-FH12NA, MSZ-FS12NA, MXZ-2C20NAHZ

Last verified for technical accuracy on March 14, 2026