What you came for
F4 E6 is a report, not a diagnosis: it says the control saw the waveguide area run hotter than it allows and stopped. The oven side of a combination unit may be fine, but do not keep running microwave power while this stands. Work down the ranked causes rather than ordering the part the code names.
This code, as the manufacturer publishes it
Reference| Code | Documented meaning |
|---|---|
| F4 E6 | There may be a problem with the Microwave Wave Guide Temperature Sensor, or the associated wiring. |
What an owner observes
- The microwave stops part-way through and shows the code — Heat builds with run time, so the fault arrives during a cycle rather than at the start.
- A smell of scorching from inside the cavity — Food debris in the channel burns and takes the temperature up with it.
- NEAR MISS - arcing and bright flashes inside the cavity — Arcing is more urgent than this code: stop, unplug, and call.
What is usually behind it
- A blocked or covered air path — Ranked first because it needs no part: an intake behind a cupboard door or an exhaust covered by a tray lets normal running heat accumulate until the reading goes out of range.
- Food debris or a damaged cover in the waveguide channel — Second: anything burning in the channel puts heat exactly where this reading is taken.
What to check first, second and third
- Clear everything from the vents and try again — Free, and it is the most common cause of the whole family.
- Look at the waveguide cover inside the cavity — Scorching or a hole in it is a service item and an important one.
What an owner can safely do
- Clean food residue out of the cavity, especially near the cover — Debris in the channel is what burns and drives the reading up.
Tools: soft clothAbout 15 min
- Run a short heating attempt and listen for the fan — Fan audible, no code, and the repair is finished.
About 5 min
- STOP HERE if the waveguide cover is scorched or holed — Do not open the cabinet: the capacitor holds a lethal charge after the appliance is unplugged.
Safety first, and it is not optional
Safety
Microwave safety is different in kind from the rest of the kitchen. The capacitor in the power circuit stores a lethal charge after the appliance is unplugged, so unplugging is a precaution and not a fix. Unplug it or switch off its breaker, keep the cabinet shut, and leave the interlocks as the manufacturer fitted them.
When to stop and call someone
Unplug it and call now if you see arcing, a scorched or holed cover, or smell burning. Microwave energy escaping a damaged channel is the one failure mode here that is genuinely urgent. In the ordinary case, call when the vents are clear, the cavity is clean and the code still arrives: a cooling fan, a waveguide cover and a sensing circuit are all service items behind a cabinet owners do not open.
Codes read alongside this one
What this page does not cover
The reading on this page applies to the microwave and combination model lines that monitor waveguide temperature. Two things are deliberately absent: anything that varies by model line, such as part numbers and wiring detail, and anything the manufacturer publishes only to technicians. Where a page exists for your specific family or model, that page takes precedence over this one, and the index linked below points to it.
The code index and nearby reading
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
