The short answer
F3T4 is a sensing fault: the Maytag table records it against the Magnetron Temperature Thermistor, meaning the control could not read a usable value from that circuit. The oven will normally refuse to heat or drop out of its cycle. Do not cook on it — a control that cannot read the cavity cannot regulate it.
Code table
Reference| code | meaning | owner-checkable |
|---|---|---|
| F3T4 | There may be a problem with the Magnetron Temperature Thermistor or the associated wiring. | no |
| F3T3 | There may be a problem with the Hood Temperature Thermistor or the associated wiring. | see page |
| F4 | There may be a problem with the Oven Cavity Control, or the associated wiring. | see page |
What you observe
- The code lands when heat is called for — Selecting bake is what makes the control read the Magnetron Temperature Thermistor.
- It returns after a power cycle — A hard sensing fault repeats within a cycle or two.
- NEAR MISS — it heats, but to the wrong temperature — Heating badly with no code is a calibration question, answered on another page.
Likeliest causes first
- The Magnetron Temperature Thermistor itself — A sensor that reads open or short hands the control a value it cannot use, which is exactly what this code reports.
- The connector and harness at the Magnetron Temperature Thermistor — The cheapest item in the circuit and the one that moves: heat cycling works a terminal loose long before the part itself drifts.
- The board input behind it — Ranked last on purpose: it is the dearest part here and the least likely, so it is proved rather than guessed.
Check in this order
- Kill the power, then look at the Magnetron Temperature Thermistor connector — A backed-out terminal or a browned housing shows before any meter comes out.
- Follow the lead for heat damage — The run from the cavity to the board passes the hottest part of the appliance.
- Measure the sensor cold, then the board input — The sensor is judged against its service value first; the board only once the sensor reads right.
Owner-safe steps
- Note the code, then cut the breaker for a minute — Separates a stored glitch from a hard fault at no cost.
About 5 min
- Let the cavity go fully cold before judging — A hot cavity makes an intermittent fault look solid.
About 60 min
- STOP HERE — the next step is a meter on the sensor circuit — That means the rear panel off, which is where an owner check ends.
Safety first
Safety
Unplug the appliance or switch off its breaker before removing any panel — a capacitor can hold a charge after the power is off. An oven carries a heavy element circuit behind the rear panel, and the cavity stays dangerous long after the heat is off. Leave the door lock and its switch wired exactly as they are.
When to call
Call once the code survives a power cycle. Everything past that sits behind the rear panel: the Magnetron Temperature Thermistor and its harness are reached with the appliance drawn out, and only a meter separates a failed sensor from a failed board input. Call sooner if you smell hot insulation or see discoloured wiring — that is the harness failing, not the sensor.
Neighbouring codes — F3T3 and F4 sit beside F3T4 and name overlapping hardware, so most checks here carry across. Read the two meanings side by side: where they differ in the part named, the order of the checks changes with them.
What this page does not cover
Generalized information: this reads F3T4 as the shared Maytag oven table records it, so it covers the model lines using that table and no others. Where a page exists for your family or model line, that one is the more specific answer — start there if your model is named. Not here: wiring colours, connector positions and part numbers, which differ by family.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
