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ErrBase

Mitsubishi Minisplit Error Codes

All Mitsubishi minisplit error codes with step-by-step troubleshooting, multimeter specs, and OEM part numbers.

11 error codes

CodeMeaning
BLINKING-LIGHTThe indoor unit is broadcasting a fault code through its LED lights, using timed blink sequences to identify which component has failed or fallen out of spec. The number of green Operation light flashes combined with red Timer light flashes maps to a specific error in Mitsubishi's service manual.
moderateintermediate
E6The indoor air handler and outdoor unit have lost the data communication signal that coordinates their operation. Without that constant handshake on the S3 line, neither unit knows what the other is doing, so both shut down completely.
highintermediate
E9The condensate drain pump has failed, is clogged, or the float switch that monitors the pump has detected a drainage failure.
moderateintermediate
HUBHub page covering all Mitsubishi Electric mini-split error codes for MSZ and MXZ series heat pumps.
lowbeginner
LEAKINGThe indoor unit can't get rid of condensation water fast enough, so it overflows the drain pan and drips out the front. This happens when the drain line's clogged, the unit's not level, the coils ice over and then melt, or the condensate pump fails. Basically the machine is producing water faster than it can move it out.
moderateintermediate
NOT-COOLINGThe system is running but not producing cold air. Either the compressor isn't engaged, refrigerant isn't circulating, or the indoor unit is set to a non-cooling mode. Could also be a sensor sending bad temperature data, or a communication break between the indoor and outdoor units that's preventing the compressor from getting the run signal.
moderateintermediate
NOT-HEATINGThe mini-split's heat pump cycle has broken down. Either the outdoor unit can't extract heat from the air due to temperature limits, ice blockage, or low refrigerant, the reversing valve isn't switching to heat mode, or a sensor is feeding the control board bad data and it's refusing to run heating at all.
moderateintermediate
P4The condensate drain pan under the indoor unit's evaporator coil has filled with water, indicating the drainage system is blocked or failing.
highbeginner
P5The drain float switch inside the indoor unit has been triggered due to water accumulation in the drain system, indicating drainage cannot keep pace with condensate production.
highintermediate
P6The current transformer (CT) sensor on the outdoor unit has detected an abnormal current condition - either the sensor itself has failed or the compressor is drawing abnormal current.
highadvanced
P8The indoor evaporator coil dropped below the freezing threshold, so the control board shut down the compressor to prevent ice damage. Basically, either not enough warm air is flowing across the coil, or the refrigerant pressure is too low and it's boiling at the wrong temperature.
highadvanced