Denso Air Conditioner Error Code E16

E16 indicates a compressor phase interruption abnormality, meaning the control board has detected that one of the three phases delivering current to the compressor motor is reading 0 amperes. This causes the unit to shut down to protect the compressor from damage. The fault points to a wiring, connection, or relay board issue in most cases.

A reset can clear the E16 code temporarily, but if the underlying wiring or component issue has not been resolved, the fault will return as soon as the system attempts to run the compressor again. Always inspect and correct the wiring connections before resetting so the reset is meaningful rather than just masking an active fault.

Repair costs vary widely depending on the root cause. If the fix is simply reseating a loose connector, the cost may only cover a service call, typically in the range of $75 to $150. Replacing a relay board can add $150 to $400 in parts and labor. A failed compressor is the most expensive outcome, with replacement costs potentially ranging from $600 to $1,500 or more depending on the unit size.

The first recommended step is to inspect and reseat all wiring connections at the compressor and relay board, then reset the controller. This is a task a knowledgeable DIYer can attempt, but working with three-phase compressor wiring carries serious electrical hazards. If the fault returns after reseating connections, further diagnosis involving live current measurements should be performed by a qualified technician.

No. The unit will not operate normally while E16 is active because the control board shuts down the compressor to prevent motor damage from single-phasing. Attempting to repeatedly restart the unit without correcting the fault can cause additional stress to the compressor motor windings and potentially worsen the damage.