The reading in two sentences
Read E33 as this: detergent foam has been detected, from too much detergent or an old detergent, and it is more likely on lightly soiled loads. The machine is usable; it is reporting the detergent rather than a fault, so the change needed is in the dose. You can settle whether this is a one-off or a real fault yourself; naming the failed part is not owner work.
Error codes
Reference| Code | Meaning |
|---|---|
| E33 | Detergent foam has been detected. Too much detergent or an old detergent was used. This may cause excessive foaming from the detergent compartment. This may happen when washing lightly soiled items. |
What else is happening when this shows
- Extra rinses added and a spin that will not reach speed — The machine deals with foam before it reports it, which is why the cycle runs long.
- The cycle runs long, with extra rinses — The control adds rinses to get rid of foam before it reports anything.
- NEAR MISS — no foam anywhere and the same code — Without foam, look at the sensing side instead: that is a different fault with the same symptom.
What triggers E33, most likely first
- Too much detergent for the load — It goes first because the published description names it: dose instructions assume a full, soiled load in hard water, and the same dose in a small or lightly soiled load foams heavily.
- An old or unsuitable detergent — The description names this too: product that has aged or that was never meant for this machine foams by design, and no dose adjustment resolves it.
- Very soft water — Last, and the one people never suspect: soft water needs markedly less product, and a dose that suits a hard-water area foams heavily in a soft one.
The order to work through
- Compare the dose you used against the product instructions for that load — Most overdosing is by a factor of two or more, and this is where it shows up.
- Look through the glass during the wash for foam — Seeing it confirms the code is reporting what it says it is reporting.
- Body: Look at the product before the machine: type, dose, load size and water hardness explain almost all of these codes between them.
The reset and the checks that follow it
- Run a rinse or a spin to clear the foam — No product. Repeat if foam is still visible through the door at the end.
About 30 min
- Run a rinse and spin with no product, then halve the dose for the next few loads — Repeat the rinse if foam is still visible through the glass at the end.
About 40 min
- Halve the dose for the next few cycles and watch — Most overdosing is by a factor of two or more, and results rarely suffer from the reduction.
About 10 min
- STOP HERE if the code appears with no foam and a correct dose — That is a sensing fault rather than a foam one, and it needs the appliance open.
Before a panel comes off
Safety
Unplug the machine or switch off its breaker before any panel comes off — a capacitor can hold a charge after the power is off. Close the supply tap before touching a hose, expect standing water when a filter comes out, and never work round the door interlock.
Where an owner check ends
Call if foam is escaping from the cabinet rather than staying in the drum, or if the code persists after an empty maintenance cycle and a reduced dose.
Other codes on a Bosch washing machine
What is deliberately not here
Treat this as the general Bosch washing machine reading. It stops short of anything model-specific — part numbers, harness colours, connector layouts and service-mode entry — because those differ by family and a technician takes them from the rating plate rather than from a code. A family- or model-specific page, where one exists, is linked from the code index below and is the closer answer.
Links: - [Bosch washing machine error codes](/blog/bosch-washer-error-codes)
Next steps
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
