Error code · Freezer

Frigidaire Upright Freezer Code O or E9: Open Thermistor

Medium · inspection needed

Code: O or E9
Appliance: Freezer
Brand: Frigidaire
Warranty: 30-day workmanship

What O or E9 means

An O or E9 on Frigidaire upright freezers with electronic control, including the Deluxe half-moon, vertical, square and rectangle control boards, such as FPUH19D7LF, means an open thermistor. The control reads the temperature sensor circuit as broken or disconnected, as if the wire had been cut. Without that reading the freezer cannot control its temperature, and it may run too long or too little. These older freezers are still common, and we repair them.

Common causes of O or E9

The thermistor and its plug
A broken wire or loose terminal in the sensor wiring
The control board input

✓ One safe check you can try

1. Confirm the freezer has power and the door is closed. 2. Pull the plug for a minute and put it back. 3. Feel inside after a few hours to see whether it is staying cold. 4. If the code returns, protect the food and call us to schedule service.

! Why to stop there

O or E9 says the circuit is open, but not whether it is the sensor, the wire or the board.
We test the sensor and the plug first, since a loose connection is simpler than a board.
Our price is in writing before work, and we say plainly if an older freezer is not worth the repair.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

→Same appliance

Other Freezer codes

S or E8Frigidaire Freezer Reading S or E8, Which Means a Shorted Thermistor Door AjarWhat the Door Ajar Alarm on a Frigidaire Freezer Means E or E1Frigidaire Upright Freezer Showing E or E1: Thermistor Error E2Frigidaire Upright Freezer Reports E2 As a Stuck Key E5Showroom Mode E5 on a Frigidaire Upright Freezer E7E7 on a Frigidaire Upright Freezer: Stuck Key or Fail-Safe Mode HIHigh Temperature Reading HI on a Frigidaire Upright Freezer High TempWhy a Frigidaire Upright Freezer High Temp Alarm Sounds

O or E9O or E9 questions

Is O the opposite of S?

O means the thermistor circuit reads open. S means it reads shorted. Both mean the control has lost its temperature reading. An open reading means the wire path to the sensor is broken or disconnected.

Can the freezer keep running with E9?

It may run, but without a trustworthy reading it can cool too much or too little. Check the temperature inside. That is often a connection and not the sensor.

Is a thermistor repair expensive?

The part is usually modest, but we give a written price before any work and tell you plainly if an older freezer is not worth fixing. A loose plug is the simplest cause we check first.

Book a visit

Still seeing O or E9?

A technician diagnoses it on site and gives you the price in writing before any work starts.

(713) 844-8518