Bosch Dishwasher Error Codes

Summary

Bosch is one of the highest-volume dishwasher brands in the UK, sold under the Bosch nameplate and shared platforms with Neff and Siemens (all part of BSH Hausgeräte). The domestic range spans decades of model generations — from older SMS/SMV-prefixed models with simple light-flash diagnostics through to current Series 2–8 models with full digital displays, and the newest Home Connect app-enabled dishwashers that surface fault text directly on a smartphone rather than requiring a code to be looked up at all.

Because the range is so broad, Bosch has never used one single fault-code table for the whole lineup. Older and budget models without a numeric display use a "flash code" system: the Start button LED and/or a row of programme-stage lights flash in a specific pattern (a count of flashes, sometimes with a pause and a second count) that maps to a fault category. Mid-range and premium models with a digital display show a direct alphanumeric code, typically in the E0X or E1X–E3X format. This split matters on site — quoting an E-code number to a customer with a flash-only model is meaningless, and vice versa. The first job on any Bosch dishwasher fault is establishing which display type is fitted, then reading the model number (ENr) and FD (production date) code off the rating plate, usually on the door edge or door frame when the door is open, so the fault can be checked against that specific model's documentation.

This guide covers the fault categories that recur across the range — water inlet/Aquastop, heating/NTC sensor, drainage/pump, and electronic/PCB faults — with the DIY-fixable checks a competent person can do before calling an engineer. Specific code numbers are given only where consistently documented across multiple current models; elsewhere a fault is described by category only, to avoid quoting a number that may not apply to the model in front of you.

Key Facts

• Two display types — older/budget models use flashing light sequences (Start button LED + programme lights); mid-range and premium models use a direct digital E-code display
• Code format on display models — typically E followed by two digits, e.g. E01, E15, E24; the leading digit groups the fault area on many models but this is not universal across all generations — confirm against the specific model
• Rating plate location — inside the door, on the edge or frame; shows the ENr (model number) and FD (production/batch code), both needed to look up the exact fault table for that unit
• Home Connect models — app-enabled dishwashers can surface a plain-language fault description in the Home Connect app in addition to, or instead of, an on-panel code
• Aquastop — Bosch's proprietary leak-protection system; a triggered Aquastop float switch cuts water supply and locks the machine — this is a safety trip, not necessarily a leak in progress, and needs the float chamber and hose checked before assuming a major fault
• Aquastop/water-inlet faults — no-fill, slow-fill, or water-inlet valve faults are among the most common non-electronic callouts, often caused by a kinked supply hose, closed isolation valve, or blocked inlet filter rather than a failed valve
• Heating element/NTC sensor faults — cover both a failed heating element and a failed NTC (temperature sensor); these often show similar symptoms (poor wash results, wrong reported temperature) so both should be checked together
• Drainage/pump faults — blocked filter basket, kinked or high drain hose, or a failed drain pump motor; filter basket blockage accounts for the large majority of drainage callouts and is the first and easiest check
• Electronic/PCB faults — control board or wiring faults; these are the least DIY-fixable category and usually require a qualified appliance engineer, as they may involve mains-voltage components
• UK hard water regions — limescale build-up on the heating element and NTC sensor is a genuine and common contributing cause of heating-related faults in hard water areas (much of the South East, East Anglia, and parts of the Midlands) — see water softeners for softener options
• Salt and rinse aid settings — an incorrectly set water hardness dial or empty salt reservoir won't usually trigger a fault code but is a common cause of poor wash results mistaken for a sensor fault
• Electrical safety — a qualified person should carry out any work involving the flex, plug, fused connection unit (FCU), or internal wiring — see kitchen appliance circuits for the FCU/13A spur requirement
• Water Regs — installation and waste connection must comply with the Water Supply (Water Fittings) Regulations 1999 — see dishwasher vs washing machine plumbing for fluid category and backflow requirements
• WEEE Regulations — a faulty dishwasher scrapped rather than repaired must go via a registered WEEE take-back scheme or recycling centre, not general waste
• Manual reset — most lockouts clear with a power-cycle reset (isolate at the FCU/plug, wait around a minute, restore power); a fault returning immediately points to a genuine component fault, not a nuisance trip
• Repeated resetting risk — repeatedly resetting a heating or electronic fault without investigating risks compounding it — diagnose before repeat-resetting

Quick Reference Table

This table intentionally omits precise code numbers where they are not consistently documented across the current Bosch range. Always confirm the exact code against the fault code table printed in the user manual, or on Bosch's own service documentation, for the specific ENr model number on the rating plate.

Detailed Guidance

Fault-Finding Decision Tree

START: Bosch dishwasher showing a fault (code, flash sequence, or app alert)
│
├─ STEP 1: Identify display type
│   ├─ No display, flashing lights only → note the flash pattern
│   │   (Start LED count, or programme light sequence) and check
│   │   against the model's own manual — flash codes are NOT
│   │   standardised across the whole Bosch range
│   ├─ Digital display → read the E-code shown
│   └─ Home Connect app → check the app for a plain-language
│       fault description, which is often clearer than the code
│
├─ STEP 2: Read the rating plate (inside the door edge/frame)
│   → note ENr (model number) and FD (production code) —
│     needed to confirm the fault meaning against the correct
│     model-specific table before ordering parts
│
├─ STEP 3: Which fault category?
│   ├─ WATER INLET / AQUASTOP → go to INLET BRANCH
│   ├─ HEATING / NTC SENSOR → go to HEATING BRANCH
│   ├─ DRAINAGE / PUMP → go to DRAINAGE BRANCH
│   └─ ELECTRONIC / PCB / erratic behaviour → go to
│       ELECTRONIC BRANCH
│
├─ INLET BRANCH
│   ├─ Check the isolation valve under the sink is fully open
│   ├─ Check the inlet hose for kinks or crushing
│   ├─ Check the inlet filter (small mesh filter where the hose
│   │   connects to the machine) for limescale/debris blockage
│   ├─ Check for water pooled in the base tray — if present,
│   │   this is a genuine Aquastop leak trip, not a nuisance fault
│   └─ If supply, hose and filter all check out → inlet valve
│       likely faulty → competent appliance engineer
│
├─ HEATING BRANCH
│   ├─ Check the wash results and reported temperature —
│   │   consistently poor washing at low temperature suggests
│   │   element or NTC fault rather than a one-off
│   ├─ In a known hard-water area, check salt reservoir and
│   │   water hardness dial setting first — limescale build-up
│   │   on the element/sensor is a common contributing cause
│   ├─ STOP — element and NTC replacement involves mains-voltage
│   │   internal components
│   └─ → qualified appliance engineer required
│
├─ DRAINAGE BRANCH
│   ├─ Check and clean the filter basket at the base of the tub
│   │   first — this alone resolves the large majority of
│   │   drainage faults
│   ├─ Check the drain hose for kinks and that its highest point
│   │   does not exceed the manufacturer's maximum height
│   ├─ Check the non-return valve/air gap in the drain hose
│   │   connection (often at the sink waste or under-sink spigot)
│   │   for blockage
│   └─ If filter, hose and non-return valve all check out →
│       drain pump motor likely faulty → competent-DIY for an
│       experienced person, or appliance engineer
│
└─ ELECTRONIC/PCB BRANCH
    ├─ Power-cycle reset (isolate at least 1 minute) — note
    │   whether the fault returns immediately
    ├─ Check the door catch/interlock — many "electronic-looking"
    │   faults (endless beeping, cycle won't start) are actually
    │   a door not latching correctly
    ├─ Check flex, plug and FCU/spur for any visible damage
    │   (visual check only — do not open the FCU/spur)
    └─ If fault persists after reset and door/wiring visual check
        → qualified appliance engineer; PCB and wiring faults are
        not a DIY repair

Reading Flash Codes on Non-Display Models

Older and budget Bosch dishwashers (many models in the SMS/SMV/SMU numbering without a digital screen) signal faults by flashing the Start button light and, on some models, one or more programme indicator lights in a repeating pattern — a count of flashes, sometimes followed by a pause and a second count, which together identify the fault. The specific flash-count-to-fault mapping is not standardised even within Bosch's own older range — it varies by model generation, so don't assume a flash count means the same fault on two different SMS-prefixed models without checking that model's manual. If the manual isn't available, the flash pattern described precisely (e.g. "Start light flashes 3 times, pauses, flashes twice, repeats") plus the rating plate ENr number is usually enough for Bosch support or a competent appliance engineer to identify the fault correctly.

Water Inlet and Aquastop Faults

Aquastop is Bosch's branded leak-protection system, fitted to the water inlet hose on most current models. It monitors for water in the machine's base tray; if detected, a float switch trips, cuts the supply via a solenoid valve built into the hose assembly, and locks the machine. This is a safety feature working correctly, not necessarily evidence of a major leak — but it should never be reset and ignored without checking for standing water in the tray, since an unaddressed leak can damage flooring and units below.

The more common inlet fault in practice is the opposite problem — no water intake at all, or a very slow fill. Before assuming a faulty inlet valve: confirm the isolation valve is fully open, check the inlet hose for kinks, and check the small mesh inlet filter where the hose connects to the machine — a common site of limescale and debris blockage in hard-water areas, and straightforward to remove and clean. Only once supply, hose and filter are confirmed clear should the inlet valve itself be suspected as faulty.

Heating Element and NTC Sensor Faults

The heating element and the NTC (Negative Temperature Coefficient) thermistor sensor are grouped together here because their symptoms overlap — both present as poor wash/dry results, a cycle running unusually long trying to reach temperature, or a temperature-related fault code. A failed element won't heat the water; a failed NTC sensor reports the wrong temperature to the control board, causing the machine to under-heat or run an extended heating phase trying to reach a temperature it isn't actually measuring correctly.

In UK hard-water regions, limescale deposits on the heating element are a genuine contributing factor — scale acts as an insulator, making the element work harder and can eventually contribute to failure. Checking the water hardness dial matches the local supply, and that salt is topped up, is a legitimate first check before assuming a component fault — see water softeners for whole-house softening options.

Both element and NTC sensor sit inside the tub and involve disconnecting mains-voltage wiring to replace — not a DIY job; use a qualified appliance engineer.

Drainage and Pump Faults

Drainage faults are consistently the single most common Bosch dishwasher callout category, and the filter basket at the base of the tub is responsible for the large majority of them. Food debris, glass fragments, and general residue collect there over time; if not cleaned regularly, it restricts water flow enough to trigger a drainage fault or leave standing water at the end of a cycle.

After the filter basket, check the drain hose for kinks and confirm its highest point doesn't exceed the maximum height in the installation instructions (exceeding it prevents the pump clearing the loop). The drain connection should include a non-return valve or air gap per the Water Supply (Water Fittings) Regulations 1999 — a blocked or missing valve can also present as a drainage fault. Only once these are ruled out should the drain pump motor itself be suspected.

Electronic and PCB Faults

This is the category with the least scope for DIY intervention. Genuinely erratic behaviour — an unresponsive control panel, cycles stopping partway with no clear code, or garbled display output — usually points to a control board or wiring fault. Always rule out the door catch/interlock first, since a door not latching correctly can produce symptoms (endless beeping, a cycle that won't start) that look electronic but are mechanical. A visual check of the flex, plug and any FCU for obvious damage is reasonable, but any repair beyond that — especially opening the control panel housing or the FCU/spur — should go to a qualified appliance engineer.

Frequently Asked Questions

My Bosch dishwasher has no digital display — how do I get a fault code?

Models without a display use a flash-code system instead — the Start button light, and on many models one or more programme-stage lights, flash in a repeating pattern that maps to a fault category. Note the exact pattern (how many flashes, any pause, whether it repeats) and check it against the specific model's user manual, since the flash-to-fault mapping varies between Bosch model generations. The rating plate inside the door gives the ENr model number needed to find the correct manual or fault table.

Can I reset a Bosch dishwasher fault myself?

For most faults, a power-cycle reset (isolate at the plug or FCU for about a minute, then restore power) is a reasonable first step and clears nuisance trips. If the fault returns immediately or within the next cycle, stop resetting and diagnose the cause instead — repeated resets on a genuine heating, drainage, or electronic fault risk making it worse.

Is a specific Bosch fault code the same across all their dishwasher models?

No. The range spans many generations and platforms (flash-code models, digital-display Series 2–8 models, Home Connect app models), and there is no single universal code table. The same number can mean different things on different generations — always confirm against the fault code table for the specific ENr model number on the rating plate.

Should I call an engineer or try to fix it myself?

Water-inlet checks (isolation valve, hose kinks, inlet filter cleaning) and drainage checks (filter basket, drain hose routing) are reasonable for a competent person. Anything involving the heating element, NTC sensor, control board/PCB, internal wiring, or the flex/plug/FCU connection should go to a qualified appliance engineer — these involve mains-voltage components.

Regulations & Standards

• Water Supply (Water Fittings) Regulations 1999 — governs the dishwasher's water inlet and waste/drain connection, including backflow prevention (non-return valve/air gap) at the drain point

• Waste Electrical and Electronic Equipment (WEEE) Regulations 2013 — a scrapped dishwasher must be disposed of via a registered take-back scheme or household waste recycling centre, not general waste

• Part P of the Building Regulations — only engages if the fault-finding or repair involves installing a new dedicated circuit or fixed wiring alteration for the appliance's electrical supply; routine appliance repair on an existing circuit does not require Part P notification

• BS 7671:2018+A4:2026 (IET Wiring Regulations) — applies to the dedicated circuit, FCU/spur, and isolation arrangements supplying the dishwasher, relevant if any electrical fault-finding extends to the fixed wiring rather than the appliance itself

• Bosch Home UK — Dishwasher Support and Error Code Guidance — model-specific fault code tables and manuals by ENr number

• GOV.UK — Waste Electrical and Electronic Equipment (WEEE) Regulations — disposal requirements for faulty appliances

• Water Regs UK — Water Supply (Water Fittings) Regulations 1999 Guidance — backflow prevention and drain connection requirements for dishwashers

• Bosch Home Connect App Support — app-based fault reporting for Home Connect-enabled models

• dishwasher not draining — detailed drainage fault decision tree: filter basket, drain hose, pump impeller, drain pump motor

• dishwasher leaking — door seal, detergent foaming, door alignment, and float-switch overfill diagnosis

• dishwasher not cleaning properly — poor wash result causes: spray arm blockage, filter, detergent dosing, limescale, wash pump

• water softeners — whole-house softening to address hard-water limescale affecting heating elements and NTC sensors

• dishwasher vs washing machine plumbing — fluid category and Water Regs compliance for dishwasher plumbing connections