Miele Dryer Error Code F4

F4 indicates an open circuit in the fill ring temperature sensor, designated 1R30. The control board is reading a resistance value that corresponds to a temperature below -5°F (-15°C), which is an impossible reading under normal conditions and signals a break in the sensor circuit. The fault is almost always caused by a wiring or connector issue rather than an actual temperature problem inside the dryer.

It is not advisable to continue operating the dryer while the F4 fault is active. The fill ring temperature sensor is part of the system that monitors and controls heat levels during the drying cycle. Running the dryer without a functioning sensor means the control board cannot accurately detect overheating conditions in that area, which could pose a safety risk.

A reset may temporarily clear the F4 error from the display, but the fault will return as soon as the control board checks the fill ring sensor circuit and reads the open circuit condition again. The underlying wiring, connector, or sensor issue must be diagnosed and repaired to permanently resolve the error code.

A knowledgeable DIYer can begin by checking the sensor connector and wiring harness for obvious damage or a loose plug, since reconnecting a disconnected connector requires no special tools. However, testing sensor resistance and tracing wiring faults through the dryer cabinet does require a multimeter and some disassembly. Replacing the fill ring temperature sensor itself is a more involved repair that many homeowners prefer to leave to a qualified technician.

If the fix is simply reseating a loose connector, there may be no parts cost involved, though a service call fee typically applies. If the fill ring temperature sensor 1R30 needs replacement, parts and labor costs combined generally range from around $150 to $350 depending on your location and the service provider. A wiring harness repair can fall within a similar range depending on the extent of the damage.