JennAir OTR Microwave Code F4E4: humidity thermistor

What F4E4 means

JennAir over-the-range microwave hoods, including the JMV9196CS and JMV8000 series, show F4E4 when there may be a problem with the Humidity Thermistor or its wiring. This sensor helps the control judge moisture and steam during sensor cooking. When the reading is lost, the code appears and sensor-based cooking programs may not work. The rest of the microwave generally keeps working, and timed cooking is unaffected.

Common causes of F4E4

Humidity Thermistor has failed open or shorted
Wiring to the humidity sensor damaged
Steam or grease affecting the sensor area

✓ One safe check you can try

1. Let the microwave cool and wipe the interior and the area around the vents clean. 2. Cancel and switch the breaker off for a minute, then back on. 3. Cook something with a set time instead of a sensor program. 4. If F4E4 remains, call us.

! Why to stop there

The humidity sensor is not reachable without removing the microwave.
Cooking with a bad sensor can undercook or overcook food.
We quote the work first.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

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Other Microwave codes

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F4E4F4E4 questions

Can I still use the microwave when F4E4 shows?

Often yes, for timed cooking. Sensor programs may not work until the thermistor is replaced. Use plain time settings and keep an eye on the food, since automatic sensing is the part that is affected.

Why does steam matter to this code?

Heavy steam and grease can build up around the sensor area. Wiping what you can reach helps, but a failed thermistor needs a replacement. Wipe gently with a damp cloth.

What will the visit involve?

We test the thermistor and its circuit, and quote the price in writing before any repair. If the thermistor is the cause, we tell you the full cost, including the part and labor, before we begin work.