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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-LIGHTCauses and Fixes
mediumintermediate
E6The indoor air handler and outdoor unit have lost the data communication signal that coordinates their operation.
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
LEAKINGCauses and Fixes
mediumintermediate
NOT-COOLINGOutdoor Unit, Refrigerant, and Sensor Fixes
mediumintermediate
NOT-HEATINGCauses and Fixes
mediumintermediate
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 coil temperature has dropped below the safe operating threshold, triggering freeze protection. This is commonly caused by low refrigerant charge or severely restricted airflow.
highadvanced