Wolf Early Induction Cooktop Code F4: rear zone sensor open

What F4 means

Early Wolf induction cooktops, such as the CT30I/S and CT36I/S, show F4 when the temperature sensor on the rear cooking zone reads open. The control receives no signal from that sensor, so it will not heat the rear zone. You see F4, and the rear burner stays off. The front zone may keep working, since it has its own sensor and circuit.

Common causes of F4

Open circuit in the rear zone sensor
Loose or unplugged sensor connector
Broken sensor lead under the glass

✓ One safe check you can try

1. Switch off the cooktop and let it cool. 2. Turn the wall disconnect off for 60 seconds, then turn it on again. 3. Test the front zone with a flat magnetic pan. 4. Should F4 reappear, leave it off and book a visit. Do not open the cooktop.

! Why to stop there

An open lead needs tracing under the glass.
We test the sensor and its connector before ordering anything.
Expect the price in writing before work.
Our visit has a 30-day workmanship warranty, confirmed in writing.

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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F4F4 questions

What is the difference between F3 and F4?

F3 is a shorted rear sensor and F4 is an open rear sensor. The two electrical conditions call for different checks under the glass, so the letter matters.

Does F4 mean the glass is hot?

No. It means the control cannot read the sensor at all. The glass can be completely cold and the code will still show on the display.

Can you fix only the sensor?

Often yes. We confirm which part failed, then quote just that part and the labor, in writing, before any work starts, so you know the full cost first.