JennAir Built-In Microwave Code F8 E4: exhaust air sensor

What F8 E4 means

On JennAir built-in microwaves and combination wall oven microwave cavities such as the JMC2427LL, F8 E4 means there may be a problem with the Exhaust Fan Air Temperature Sensor or its wiring. The sensor reads how warm the air leaving the unit is. You will see the code, and the control may limit or stop operation because it cannot check exhaust heat.

Common causes of F8 E4

Exhaust Fan Air Temperature Sensor shorted or broken
Wiring to the exhaust sensor damaged
Control not reading the exhaust sensor

✓ One safe check you can try

1. Let the unit cool with the door open. 2. Clear the exhaust vent opening of anything that blocks it. 3. Turn the breaker off for one minute, then on. 4. If F8 E4 persists, stop using the unit and call us. Do not try to reach the exhaust sensor.

! Why to stop there

The sensor sits in the exhaust path, behind panels.
A bad sensor and a bad wire look alike without testing.
We quote in writing before doing any work.

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.

→Same appliance

Other Microwave codes

FC E7JennAir OTR Microwave Code FC E7: no connection to your router FC E8JennAir OTR Microwave Code FC E8: registration rejected, check the SAID number FCE8JennAir OTR Microwave Code FCE8: wrong appliance type or model chosen Flashing 0:00JennAir Countertop Microwave Message Flashing 0:00: Reset the Clock Flashing ":" or PF in displayJennAir OTR Microwave Message Flashing ":" or PF: Power Failure or Clock Off LOC or "L" or Padlock IconJennAir Microwave Message LOC, L or Padlock Icon: Control Lock Enabled Locked, Lock or LocJennAir Built-In Microwave Message "Locked, Lock or Loc": Control Lock On ":" or "." in displayJennAir Built-In Message ":" or "." in display: clock needs setting

F8 E4F8 E4 questions

How is F8 E4 different from the other F8 codes?

The others name an airflow restriction or the cooling fan. F8 E4 names the exhaust fan air temperature sensor, which measures the heat of the outgoing air.

Could the fan itself be fine?

Yes. This code points at the sensor reading, not the fan, so the fan may still be running normally. Do not run the unit if the fan sounds odd, though.

Is a sensor replacement quick?

Usually it is a one-visit repair when the part is available. We confirm the price first and cover our work for 30 days. Tell us your model so we bring the matching sensor.