TM
Whirlpool Refrigerator
Severity: ModerateWhat Does This Error Mean?
The TM error on a Whirlpool refrigerator indicates a problem with the temperature sensor in the fresh food (refrigerator) compartment. TM stands for Temperature Mismatch or Thermistor Malfunction. The control board cannot get a reliable temperature reading from the sensor, so it cannot manage cooling correctly.
Affected Models
- WRS325SDHZ
- WRF535SWHZ
- WRT318FZDW
- WRB322DMBM
- WRS571CIHZ
Common Causes
- The refrigerator compartment thermistor (temperature sensor) has failed and is giving a bad reading
- The wiring harness to the thermistor is loose, broken, or corroded
- Moisture has gotten into the thermistor connector and caused a short circuit
- The control board is faulty and cannot process the thermistor's signal correctly
- The thermistor is positioned against a food item and is reading food temperature instead of air temperature
How to Fix It
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Check inside the refrigerator compartment for any food touching the temperature sensor.
The thermistor is usually a small plastic-tipped probe inside the fridge — near the back wall or in an air vent.
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Make sure no items are directly pressed against the back wall vents.
Blocked vents cause the sensor to read stagnant air instead of circulated air, giving inaccurate temperatures.
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Unplug the refrigerator for 5 minutes, then plug it back in.
This resets the control board. A temporary sensor glitch sometimes clears with a reset.
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Monitor the display for the next hour to see if the error returns.
Also check that the fridge compartment is cooling — place a thermometer inside and confirm it reaches 37°F (3°C).
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If TM returns after the reset, call a technician to test and replace the thermistor.
Do not ignore a persistent TM error — without accurate temperature data, the fridge cannot cool reliably.
When to Call a Professional
A TM error almost always requires a technician to properly diagnose. A multimeter is needed to test whether the thermistor is within the correct resistance range. If the thermistor is confirmed faulty, it is a relatively inexpensive part to replace ($10–$30). With labor, expect total repair costs of $80–$160.
Frequently Asked Questions
What is a thermistor and why does it matter?
A thermistor is a small electronic sensor that measures temperature. Think of it like a thermometer connected directly to your fridge's computer. The control board reads the thermistor constantly and adjusts cooling to hit your target temperature. If the thermistor gives wrong readings, the fridge might over-cool (freezing your food) or under-cool (letting it go warm).
Is the TM error dangerous for my food?
It can be — if the control board cannot get reliable temperature data, it may under-cool the fridge. Check the actual temperature with a thermometer placed inside. If the fridge is staying at or below 40°F (4°C), your food is currently safe. But get the error fixed soon — the situation can worsen if the board starts making bad cooling decisions.
Can I replace the thermistor myself on a Whirlpool refrigerator?
Thermistors are typically clipped or plugged into a wiring harness inside the fridge. On many Whirlpool models, the thermistor is accessible without disassembling the entire unit. If you can locate the sensor and find the correct replacement part (search your model number plus 'thermistor'), it is a DIY-friendly repair. The part itself usually costs $10–$30 on appliance parts websites.