What F4 Means
F4 on a Novotronic Miele oven is the oven PTC temperature sensor open-circuited — the control is getting no reading from the cavity at all. Note the sensor type: this generation uses a PTC sensor, where the later built-in ovens use a Pt1000 and report the same kind of problem as F05 and F06.
Common Causes of F4
- Oven PTC sensor failed open
- Break in the sensor wiring
- Connector unseated or corroded behind the fascia
- Wiring damaged where it passes a hot surface
🔧 One Safe Check You Can Try
Switch the oven off at the breaker and leave it there. Before the visit, note how the oven behaved beforehand: refusing to heat, heating without ever cutting out, or baking wildly off temperature all tell a technician something different.
⚠ Why You Shouldn't Go Further Than That
- An oven without cavity temperature feedback can drive its elements without knowing when to stop, which is not a condition to keep switching on.
- A PTC sensor has its own resistance characteristic and is not interchangeable with the Pt1000 sensors used on later Miele ovens.
- On a built-in oven of this age the appliance has to come out of its housing carefully; fixings seize and cabinetry around them is rarely forgiving.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.
Technical Reference
- Code
- F4
- Appliance
- Miele oven
- Maker documentation
- Miele owner manuals and use & care guides
- Checked
- September 2026
Code meanings can change between control generations. Before acting on a code, match the full model number on your appliance's rating label against the manual for that model. We are an independent repair service, not affiliated with Miele & Cie. KG.