Denso Air Conditioner Error Code E15

E15 indicates a compressor lock failure. During an operational self-check, the Denso controller monitors the compressor for a change in rotor position after a stop command. If no positional change is detected, the system concludes the compressor is mechanically seized and triggers the E15 fault to prevent further damage.

No, you should not attempt to force the unit to operate while E15 is active. The error indicates a potentially seized compressor, and continuing to run the system could cause electrical damage to the motor windings or further mechanical damage to connected components. Leave the unit off until it has been properly diagnosed and serviced.

A reset may temporarily clear the E15 code, but if the underlying compressor lock condition still exists, the fault will return once the controller runs its operational check again. Persistent E15 errors after two or three resets indicate a genuine mechanical failure that a reset cannot resolve. Replacing the compressor is the corrective action for a confirmed lock fault.

The first recommended step is to reset the controller two or three times, as a transient glitch can occasionally cause a false E15 reading. If the error clears and does not return, the unit may resume normal operation. However, if E15 persists after multiple resets, the compressor has mechanically failed and must be replaced by a qualified technician.

If the error is cleared by a controller reset with no recurrence, there is no parts cost involved. If the compressor has mechanically seized and requires replacement, repair costs typically range from several hundred to over a thousand dollars depending on the unit size, labor rates in your area, and parts availability. A technician inspection is the best way to get an accurate estimate.