Goodman Air Conditioner Error Code nP

The nP code stands for Window Switch Lockout and appears when the unit detects that both the LS and INN interlock inputs are open at the same time. This signals to the control board that a door or window is open in the conditioned space. The unit suspends all conditioning operations until the circuit is restored to a closed state. Closing the associated door or window is the first and most important step.

The nP lockout is not a safety hazard in itself. It is a built-in energy management and efficiency feature designed to stop the unit from conditioning a space when an opening to the outside is detected. The unit simply stops operating until the condition is resolved, which protects both efficiency and equipment longevity. There is no risk of refrigerant leak, electrical danger, or mechanical damage associated with this specific code.

If the fix is simply closing a door or window, there is no cost involved. If a door or window switch needs replacement, parts and labor typically range from $75 to $200 depending on the switch type and local labor rates. Wiring repairs can fall in a similar range. If the control board is at fault, replacement costs are generally higher, often ranging from $250 to $600 or more including parts and labor.

Start by closing all doors and windows that are connected to the unit's interlock circuit, then check whether the error clears on its own. If the code persists, inspect the door or window switch for proper alignment and test its contacts for continuity in the closed position. Also check the wiring at the LS and INN terminals on the control board for loose or damaged connections. If all physical components check out, a technician may need to evaluate the control board itself.

A simple power reset will not permanently clear the nP error if the underlying condition, an open door, window, or faulty switch, is still present. The control board will re-enter lockout mode as soon as it detects the open LS and INN inputs again. The error will only clear reliably once the interlock circuit reads as closed, either by physically closing the opening or by repairing the faulty switch or wiring.