Frigidaire air conditioner AS error code: room temperature sensor failed

What the AS code means

AS on a Frigidaire air conditioner means the room temperature thermistor has failed. The unit can no longer read the room air, so it cannot cycle properly. Frigidaire says to unplug the unit for about 30 seconds, and contact support if AS comes back.

The room thermistor sits in the air stream drawn into the unit, usually just behind the front grille or filter. The control board reads it to decide when the compressor should run. If the reading drops out or jumps to an impossible value, the board shows AS.

A power glitch can cause a one-off AS, which is why Frigidaire's first step is to unplug and restart. If the code returns, the thermistor, its wire or the board has a fault.

Common causes

Listed from most to least common.

1. Room temperature thermistor failed (open or short circuit)
2. Thermistor plug loose on the control board
3. Thermistor wire damaged
4. Brief power glitch
5. Control board fault

How to fix the AS code

Unplug the air conditioner or switch it off at the breaker before removing any panel or filter.

1. 1

   Step 1: Unplug the unit

   Unplug the air conditioner for about 30 seconds, as Frigidaire advises.

2. 2

   Step 2: Check the power supply

   Plug the unit straight into a wall outlet, not an extension cord. If the plug has TEST and RESET buttons, press RESET until it clicks in.

3. 3

   Step 3: Restart and watch

   Turn the unit on in Cool. If it runs normally for the next few hours, the code was likely a one-off.

4. 4

   Step 4: Contact Frigidaire if it returns

   If AS comes back, stop using the unit and contact Frigidaire support with the model and serial number from the label.

How to reset the Frigidaire air conditioner

1. Turn the air conditioner off with the remote or the control panel.
2. Cut the power. Frigidaire says to unplug window and portable units for about 30 seconds. For a mini-split, turn off its breaker for a few minutes.
3. Restore power and turn the unit back on. The compressor normally waits about 3 minutes before starting, so give it time before judging.
4. If the same code comes back, the fault is still there. Work through the fix steps above, or contact Frigidaire support.

Parts that may need replacing

Check your model number on the label inside the door or on the back before ordering.

• Frigidaire AC thermistorCheck prices

When to call a technician

If AS returns after unplugging, the thermistor or control board needs replacing. On a window unit that means taking it out of the window and opening the cabinet, so book a technician or contact Frigidaire.

A typical repair for this code costs $120–$300 in the US, including parts and labor. Prices vary by area and model.

Models this applies to

• Window air conditioners (including Frigidaire Gallery)
• Portable air conditioners
• Ductless mini-splits

Codes can differ slightly between models. Your owner's manual is the final word and is available from Frigidaire support.

Frequently asked questions