Lincoln Impinger Pizza Oven PROBE FAIL: Thermocouple Failed or Loose
PROBE FAIL means the thermocouple has failed or come loose from the oven control. Check that it is securely connected, and call for service if the message stays. A technician measures its resistance (about 11) and replaces it, or the oven control, if needed.
High: the control has lost its temperature signal and the oven cannot hold heat.
- Code
- PROBE FAIL
- Maker
- Lincoln
- Equipment
- Pizza ovens
- Applies to
- Impinger Advantage Digital push-button control
What does Lincoln PROBE FAIL mean?
On these push-button Impinger I ovens, the control reads the chamber temperature from a thermocouple. If the thermocouple has failed or has come loose from the oven control, there is no usable signal, and the control reads PROBE FAIL. The service manual's steps are in order. Check that the thermocouple is securely connected. Disconnect it and measure its resistance, about 11. Replace the thermocouple if it does not measure that. If it checks good, replace the oven control. The manual lists two causes: a failed thermocouple and a thermocouple disconnected from the oven control. The same text is used for the international Impinger II push-button manual. The domestic Impinger II 1100 Digital Advantage uses the message OPEN PROBE for the same condition, so PROBE FAIL belongs to the older 1450 and 1451 ovens.
Affected models and control systems
Lincoln Impinger I Models 1450 (natural gas) and 1451 (LP gas), 120 VAC 60 Hz, with push button Advantage digital controls. The domestic Impinger II 1100 Series uses OPEN PROBE instead.
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
- PROBE FAIL on the display
- Oven not heating or not holding temperature
- Burner shutting off
Possible causes
Listed in Lincoln's documentation
- Thermocouple failed
- Thermocouple disconnected from the oven control
Other likely causes — what usually sits behind PROBE FAIL on this control. A technician confirms which one it is before any part is replaced.
- A thermocouple plug pulled partly out when the control panel was moved
- Heat damage to the thermocouple lead near the oven wall
Safe checks before calling for service
- Turn the oven off and let it cool.
- Look at the thermocouple connection at the control to see that it is seated, without opening the oven body.
- Do not run the oven for baking while the message shows.
- Tell the technician if the oven is the 1450 (natural gas) or 1451 (LP gas).
How a technician diagnoses PROBE FAIL
- Read the display and confirm PROBE FAIL.
- Check that the thermocouple is securely connected.
- Disconnect the thermocouple and measure its resistance, expecting about 11.
- Replace the thermocouple if the reading is wrong.
- If the thermocouple tests good, replace the oven control.
- The control and its gas safety circuits carry line voltage.
- The resistance test needs a meter with the thermocouple disconnected.
- A false temperature signal affects the gas burner control.
How PROBE FAIL differs from similar codes
OPEN PROBE is the Impinger II 1100 Series Digital Advantage wording for the same condition; PROBE FAIL belongs to the Impinger I 1450/1451.
Technical reference
- Maker documentation
- Lincoln owner support
- Edition
- 1450digservice REV 12/6/05
- Models / control
- Impinger Advantage Digital push-button control
- Section
- Troubleshooting guide, pp. 7-8
- 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 Lincoln pizza oven error codes
Is PROBE FAIL the same as OPEN PROBE?
They describe the same condition on different oven models.
What resistance should the thermocouple read?
About 11, per the service manual.
Do I need a new control?
Only if the thermocouple tests good.
Need help with Lincoln PROBE FAIL?
A technician confirms the cause on site and gives you the price in writing before any work starts.