What this error means
Pressure sensor fault — the machine is detecting the drum as either empty or full when it should not be
The F04 error means the pressure sensor has sent a signal indicating the drum is either completely empty or completely full at a point in the cycle where neither condition should be true. This is typically caused by a blocked or kinked pressure hose preventing the sensor from reading correctly, a failed pressure sensor, or a detergent residue build-up inside the pressure hose chamber. It can also indicate an overfill situation if the inlet valve has stuck open.
What you'll need first
Affiliate links — we may earn a small commission at no extra cost to you.
Step-by-step
Symptoms to look for
- Machine fills then pauses for an unusually long time before tumbling begins
- Drum appears to fill beyond the normal level — water visible high in the door glass
- Programme stops during the fill phase with F04 displayed
- Machine empties and then immediately reports the drum as still full
Diagnostic steps
Unplug the machine and hold the programme selector for 10 seconds to discharge the control board. Leave unplugged for 60 seconds. Plug back in and run a 40-degree programme. Observe whether the drum fills normally and F04 does not reappear.
Place a spirit level on top of the machine and check in both directions. Adjust all four feet — turn anti-clockwise to raise, clockwise to lower — until the machine is completely stable with no rocking. Tighten each locking nut against the machine base once level.
With the machine unplugged, remove the top panel by undoing the two rear screws and sliding it backwards. The pressure hose is a narrow plastic or rubber tube running from a small stub on the outer drum body up to the pressure sensor — a small cylindrical or round component with an electrical connector and the hose attached to its lower port. Check the full length for kinks, cracks, splits, or disconnection at either end.
Disconnect the hose gently from both the drum stub and the pressure sensor port. Blow gently through the full length — airflow should be completely unobstructed. If restricted, flush with a small amount of warm water and dry fully before refitting. Clear the drum stub with a cotton bud if blocked with hardened detergent or limescale.
With the hose disconnected from the sensor and the wiring connector removed from the sensor terminals, test across the terminals with a multimeter. Gently blow into the hose port while watching the reading — the resistance should change as pressure increases. A sensor that reads open circuit in all states has failed and must be replaced.
Push the pressure hose firmly onto both stubs until fully seated. Replace the top panel. Run a 40-degree programme and observe the fill phase. The drum should fill to the normal level, pause briefly, then begin tumbling.
When to call an engineer
- Pressure hose is cracked, split, or has collapsed internally
- Pressure sensor reads open circuit across all terminal combinations
- Machine overfills even after the pressure hose has been cleared
- Control board relay stuck in the closed position — continuously energising the inlet valve
Frequently asked questions
What does the pressure sensor do?
Can a blocked pressure hose cause overfilling?
Is F04 dangerous?
What is the difference between F04 and F10 on an Indesit washing machine?
🎯 What is likely causing this fault?
⚠️ Estimates based on common faults — not a guaranteed diagnosis. Always verify before ordering parts.
Parts you may need
Enter your model number to filter results to your exact machine
Usually found on a label inside the door frame or on the back panel of the machine.
| Part | Approx. UK Cost | Find it |
|---|---|---|
| Pressure Switch | £10 - £25 | 🏷️ eBay UK → |
| Pressure Switch Hose | £10 - £25 | 🏷️ eBay UK → |
| Pressure Switch | £25 - £30 | 🛒 Amazon UK → |
ℹ️ Prices are approximate. Always check the part number matches your model before ordering. Not sure of your model number? Find out how to locate it here.