Mitsubishi Air Conditioner Error Code E.6

E.6 is a CPU fault variant, classified as Fault 6, on Mitsubishi air conditioners. It indicates the inverter control board's CPU has detected an error and shut down operation as a protective measure. The most common trigger is electrical noise from nearby equipment interfering with the inverter electronics. A qualified technician should inspect the electrical environment and the control board to diagnose the root cause.

No. The E.6 fault causes the unit to shut down and it will not operate normally while the code is active. Attempting to force operation in a fault state could risk further damage to the control board or other components. The unit should remain off until the fault is diagnosed and resolved.

A power reset may temporarily clear the E.6 code and allow the unit to restart, but if the underlying cause, such as electrical noise or a failing control board, is still present, the fault will return. Resetting without diagnosis is not a fix and repeated faults can indicate a worsening condition. A proper diagnosis should be completed to prevent recurring shutdowns.

Some steps, such as identifying and removing nearby electrical equipment that produces interference, are accessible to a knowledgeable homeowner. However, checking supply voltage, inspecting the inverter control board, and verifying grounding connections involve working with high-voltage components and should be performed by a qualified technician. Attempting internal repairs without proper training and safety equipment is not recommended.

Repair costs vary widely depending on the root cause. If the issue is resolved by addressing external electrical interference or grounding, costs may be limited to a service call fee, typically ranging from $75 to $150. If the inverter control board requires replacement, parts and labor combined can range from $300 to $700 or more depending on the model and local labor rates.