What F04 actually means
The machine isn't heating the water as it should, so it has stopped the cycle and flagged a heating fault.
F04 on a Teknix washing machine is a heating error. The control board expects the water temperature to climb once heating starts; if it doesn't rise as expected, or the heating circuit reads as faulty, the machine halts and shows this code. Teknix's own guidance for this fault is to call for service rather than attempt anything at home.
What usually causes it
- Failed heating element in the drum
- Faulty temperature sensor giving the wrong reading
- Heating element scaled up or open circuit
- Wiring fault between the control board and the element
- Control board fault
What you can safely check yourself
Work through these in order. Anything beyond this — panels off, testing parts, anything to do with the wiring — is an engineer's job, and not one to attempt with the machine plugged in.
- Turn the machine off at the wall for a minute, then power it back up and try a short cycle to see if the code returns
- Try a cold or cold-fill-only wash — if that completes but warm washes fail, it points firmly at the heating circuit
When to call someone
This one usually needs an engineer once you have tried the checks above. We cover Nottinghamshire, Derbyshire and Leicestershire, and it's £66 including VAT for an engineer to come out and diagnose it — £84 in total if it's repaired on the visit with no parts needed. Any parts needed are quoted on site before we fit them — you decide. Every repair carries a 90-day workmanship guarantee.
Outside our area? The explanation above still stands — take it to a local engineer and tell them the code. Knowing it saves them time and you money.