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Cooking Oil Tester (TPM) readings look wrong, show zero, or won't settle

Troubleshooting | Work out why your Cooking Oil Tester (TPM) shows 0 or odd values, and how to get an accurate reading.

Written by Freyja Jensen-Dowell

Before You Start

Most odd readings on the Cooking Oil Tester (TPM) come down to a few simple things. Check that the probe cover is off, the probe is clean, and the oil is between 40°C and 200°C.

Steps to Fix

  1. If it shows 0 or an odd value in the air, the probe cover is probably still on — remove it. If that is not it, the sensor may be dirty, so clean the probe.

  2. If the screen shows "Auto Hold TPM" and the number will not change, this is expected, not a fault — the tester has locked the last reading so you can note it down. Press H to release the hold, then immerse the probe in the oil you want to test for a new reading.

  3. Turn off the induction hob if it is on. Its field distorts the reading.

  4. If the oil is below 40°C it may be partly solid and read wrong — heat it into range.

  5. Keep the probe away from the pan wall, baskets, and utensils.

  6. Keep the probe tip between the Min and Max marks.

  7. If the reading will not settle, hold the probe still at the correct depth and wait for HOLD to appear. Do not wipe the probe mid-measurement.

If Still Not Working

If readings seem to have drifted over time, check the calibration against reference oil (see How to check the calibration on your Cooking Oil Tester (TPM)) and adjust if needed.

Why This Happens

The tester reads the polar compounds in the oil, so anything on the probe, the wrong temperature, nearby metal, or an induction field can all push the number off. Oil that is too cold has not fully melted, which also gives a false reading.

A number that will not change at all, alongside "Auto Hold TPM" on screen, usually just means Auto Hold has locked in a past reading rather than the tester measuring live.

Still Need Help?

If the tester will not hold calibration, see When to repair or replace your Cooking Oil Tester (TPM), or contact the Squizify support team.

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