Southbend Commercial Oven Error Code F4: Shorted Temperature Probe
F4 on a Southbend convection oven means the temperature probe is shorted. The manual says to check the probe wires, and if they are not shorted, to replace the probe. Turn the oven off and let it cool.
High: with the probe reading unusable, the oven cannot regulate its temperature.
- Code
- F4
- Maker
- Southbend
- Equipment
- Convection ovens
- Applies to
- Gas and Electric SilverStar / Marathoner Gold convection control (programmable and rack-timer models)
What does Southbend error code F4 mean?
A shorted probe has almost no resistance, which the controller cannot match to a real temperature. It stops heating and shows F4. The manual tells you to check the probe wires for a short, and if they are not shorted, to replace the probe. The sequence matters. A short is often not in the probe itself but in a wire that has rubbed through its insulation, or in a plug where the pins touch. A technician looks at the wires first, because replacing the probe will not help if the wires are the cause. F4 is the counterpart of F3: with F3 the circuit has no continuity, and with F4 it has too much. In both cases the controller will not run the heat without a believable reading, and the oven stays cold until the circuit is repaired.
Affected models and control systems
Southbend Marathoner Gold and SilverStar gas convection ovens, programmable and rack-timer models (GB/15PC, SLGB/15SC), and Southbend electric convection ovens EB/10PC, programmable and rack-timer models.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- F4 appears on the control display
- The oven does not heat
- The temperature display shows an impossible value
- F4 returns after restarting
Possible causes
Likely causes — what usually sits behind error code F4 on this control. A technician confirms which one it is before any part is replaced.
- Shorted temperature probe
- Insulation worn through where the probe wires pass the cavity edge
- Grease or moisture in the probe plug that bridges the pins
Safe checks before calling for service
- Turn the oven off and let it cool completely.
- Wipe grease from around the visible probe area when the oven is cold.
- Turn the oven on once to see whether F4 returns.
- If it does, note the model and call us without bending the probe or opening the panel.
How a technician diagnoses error code F4
- Read the code and confirm it is F4 on this model.
- Inspect the probe wires for a short.
- Measure the probe resistance and look for a near-zero reading.
- Check the plug for grease or moisture.
- Repair or replace the wires if they are shorted.
- Replace the probe if the wires are good.
- The probe wires run near heat and mains-powered controls.
- A resistance test needs the oven powered down.
- Wire repair in a hot oven wall is work for a technician.
How error code F4 differs from similar codes
F4 is a shorted probe, and F3 is an open probe. F2 is over temperature, and F1, F5, F6 and F8 are controller codes.
Technical reference
- Maker documentation
- Southbend owner support
- Edition
- Part No. 1181887, Rev. 1
- Models / control
- Gas and Electric SilverStar / Marathoner Gold convection control (programmable and rack-timer models)
- Section
- Troubleshooting, Interpreting displayed error codes (manual p. 42)
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related Southbend convection oven error codes
Is F4 the same as F3?
No. F3 means the probe circuit is open, and F4 means it is shorted.
Can grease cause F4?
Grease and moisture in a plug can bridge the pins and look like a short.
Will the oven overheat?
The controller stops heating when it cannot read the probe, so the oven stays cold instead.
Need help with Southbend error code F4?
A technician confirms the cause on site and gives you the price in writing before any work starts.