DIY HVAC Tools

Mitsubishi Electric mini split error code UH

Current sensor fault.

  • TypeFault
  • SystemControl board
  • Can I fix it?Technician job

What UH means on a Mitsubishi Electric

The outdoor board's compressor current sensor is reading an impossible value.

On this platform, UH is a fault: something has failed or is disconnected and needs diagnosis.

Common causes

  • A failed sensor or board.

How to fix it yourself

Do the reset and the visual checks, but the underlying repair needs a technician with a meter and the service manual.

  1. Reset the system: switch the breaker (or the outdoor disconnect) off, wait a full five minutes so the boards fully discharge, then switch it back on and restart from the remote.

Switch off power at the breaker before opening either unit. Capacitors in the outdoor unit hold a charge for several minutes after power is cut.

When to call a technician

Board-level fault.

Which Mitsubishi Electric units show UH

This page applies to Mitsubishi Electric M-Series (MSZ), Mr. Slim (PKA/PCA), Hyper-Heating H2i and MXZ multi-zone units. Mitsubishi Electric's own documentation lists UH as "Current sensor fault", the same definition used across the Mitsubishi Electric it is built on. If your unit shows a code with a different shape (for example a four-character code, or a plain number), it is from a different table; use the lookup with your exact code.

Where Mitsubishi Electric shows this code

Wall units without a wired controller signal a fault by blinking the operation indicator lamp; the code itself shows on a wired controller (MHK/PAR series) or on the wireless remote after entering its check mode (see your manual). On the outdoor unit, the control board LEDs blink the same code. P codes are indoor-unit faults, E codes are communication faults, F codes are outdoor-unit faults and U codes are outdoor-unit and compressor faults.

Other Mitsubishi Electric codes

Same part of the system as UH:

E1Remote controller control board faultE2Remote controller control board faultFbIndoor unit control board fault
P1Indoor intake (room) air temperature sensor fault (open or short circuit)P2Indoor pipe (liquid) temperature sensor fault (open or short circuit)P4Drain sensor or float switch faultP5Drain pump fault (overflow protection)P6Freeze protection (cooling) or overheat protection (heating)P8Pipe temperature abnormal (refrigerant circuit)P9Indoor pipe (condenser/evaporator) temperature sensor fault (open or short circuit)E0Remote controller signal receiving error

All Mitsubishi Electric error codes

UH on other brands

The same characters do not always mean the same thing. Check the brand on your unit.

Questions people ask

Can I reset a Mitsubishi Electric UH code myself?

Yes. Turn the system off at the breaker for five minutes, then restart it. If UH comes back, the fault is real and needs the checks above.

Is it safe to keep running a Mitsubishi Electric showing UH?

The unit will usually refuse to run, or run with reduced output, until the fault is cleared. Repeated resets do not fix anything and can mask a problem that is getting worse.

What will a technician check for UH?

Board-level fault. Ask for the measurements, not just a parts quote.

Sources

  • Mitsubishi Electric M-Series and Mr. Slim service manuals (self-diagnosis tables)

Updated September 2026. Codes and definitions vary by model year. If your manual disagrees with this page, your manual wins. Send a correction.