What does the Bosch dishwasher E03 / E0105 error code mean?

E03 (shown as E0105 on newer connected models) most often indicates an auxiliary heater relay fault on the main control board. On some models, the same code is triggered instead by a water supply problem that prevents the dishwasher from filling within the expected time.

Can I fix a Bosch dishwasher E03 / E0105 error myself?

Start by checking the water supply valve and inlet hose, since a fill issue can trigger this code on some models. If those check out and a breaker reset does not resolve it, the fault lies with the heater relay on the control board, which requires professional diagnosis and part replacement.

Why do different sources describe E03 differently?

Bosch reuses some error codes across different model series and firmware generations, so the same code can map to a different fault depending on your specific model. E03/E0105 is most commonly a heater relay fault, but on certain models it points to a water inlet issue instead. A technician confirms which applies to your unit.

Will a breaker reset clear the E03 / E0105 error?

Sometimes. If the cause was a brief power fluctuation, resetting the breaker for 30 seconds can clear the code. If E03 or E0105 returns within the next cycle or two, the underlying relay or water supply issue needs to be addressed directly.

How much does it cost to fix a Bosch dishwasher E03 / E0105 error?

If the cause is a closed valve or kinked hose, the fix is free. If the water inlet valve needs replacement, cost typically runs $130–$220 in the Boston area. If the issue is the heater relay on the control board, replacement typically costs $220–$450, parts and labor included.

E03
E0105

Bosch · Dishwasher · Error Code

Bosch Dishwasher E03 / E0105 Error Code — Auxiliary Heater Relay Fault or Water Fill Failure

Technician Recommended Also shown as: E 03 E:03 E0105

Quick Answer

The E03 / E0105 error code has two distinct meanings depending on your Bosch model generation. On most models it signals an auxiliary heater relay fault on the main control board — part of the same E01–E05 power module fault family. On some older or regional models it means the dishwasher failed to fill with water within the expected timeframe. Start with a 5-minute breaker reset regardless of which interpretation applies — this clears transient board faults and resolves a meaningful share of cases at no cost. If the code returns, check the water supply and inlet hose first (quick and free), then have a technician test the control board relay if the fill path is confirmed good.

Most models — Board relay fault

Auxiliary heater relay fault on the main control board / power module. The board's internal switching circuit for an auxiliary heating function has failed or misbehaved. Symptoms: cycle stops mid-run, dishes cold or wet, machine locks out. Repair: technician-level board diagnosis required.

Some models — Water fill failure

Dishwasher failed to fill with water in the expected timeframe. Symptoms: machine starts but aborts early, tub stays empty or near-empty. Repair: check supply valve, inlet hose, and inlet mesh filter first — these DIY checks resolve the majority of fill-failure E03 cases.

Time

10 min–2 hrs

Difficulty

Moderate–Hard

Tools

Multimeter, Torx set

DIY Cost

$0–$80

What the E03 / E0105 Code Means

E03 belongs to the same E01–E05 power module fault family as E01 and E02. Where E01 flags the heat pump motor circuit and E02 flags the primary heater relay, E03 specifically identifies a fault in the auxiliary heater relay — a second relay on the control board that governs a supplementary heating circuit (the precise function varies by model and configuration). The control board's self-diagnostic routine has detected that this relay is not behaving as expected — it may be stuck open, stuck closed, or receiving feedback inconsistent with its commanded state.

On some Bosch model lines — particularly certain older European and Australian variants — E03 is instead assigned to a water fill failure: the machine started a cycle but could not admit enough water within the allowed fill time. If your machine's tub is empty or near-empty when E03 appears, this second interpretation is likely the one that applies to your model.

E0105 is the four-digit equivalent of E03 on newer HomeConnect-era models. Bosch's own published guidance for E0105 is direct: contact Bosch Customer Support — there is no breaker-reset step listed, unlike E0106 and E0107. This reflects the fact that E0105 almost always points to a power module hardware fault that requires a factory-trained engineer and a programmed replacement board.

Despite this, a breaker reset is still worth trying first. Power events can leave control board registers in an error state that clears with a proper power-down, and this costs nothing to attempt before arranging a service call.

Common Causes — Most Likely First

Transient control board fault from a power event. A power outage, voltage spike, or tripped breaker mid-cycle can corrupt the auxiliary relay's logic register, producing E03/E0105 without any hardware having actually failed. A full 5-minute breaker reset clears this and is always the first step. Common

Failed auxiliary heater relay on the control board. The relay contacts have burned, welded open, or otherwise failed. The control board detects unexpected feedback from the relay circuit and raises E03. Symptoms include cycles stopping mid-run, no auxiliary heating function, and the code returning immediately after a reset. Common — needs technician

Closed or partially closed water supply valve (fill-failure models only). The shut-off valve under the sink is not fully open, restricting water flow below what the machine needs to fill in time. This is the single most common cause of E03 on models where the code means water fill failure. Very common — fill-failure models

Kinked or blocked inlet hose (fill-failure models only). A sharply bent supply hose or one clogged with sediment prevents adequate water flow, causing the machine to time out on filling and display E03. Common — fill-failure models

Clogged inlet hose mesh filter (fill-failure models only). The small screen inside the inlet hose fitting is blocked with mineral deposits or debris, reducing water flow to the point where the tub can't fill within the allowed time window. Common — fill-failure models

Loose or corroded wiring to the auxiliary relay circuit. A damaged or unseated connector on the wiring harness between the relay and its associated component can break the circuit feedback loop, causing the board to register a relay fault even when the relay itself is intact. Occasional

Broader power module / control board failure. Damage beyond the auxiliary relay — internal board corrosion, a failed capacitor, or generalised component wear — causes the relay circuit diagnostics to fail. Bosch's locked-down power module programming means replacement requires a certified engineer. Less common — needs technician

How to Fix the E03 / E0105 Error — Step by Step

Determine which interpretation applies to your model

Look at what the machine was doing when E03 appeared. If the dishwasher started a cycle, ran briefly, then stopped with E03 and the tub is empty or barely filled — your model is using E03 as a water fill failure code. Work through Steps 2–4 below. If the machine ran for several minutes, appeared to be washing, then stopped — E03 is a relay fault. Skip to Step 5. If you are unsure, work through all steps in order.

Reset the circuit breaker for at least 5 minutes

Trip the dishwasher's circuit breaker and leave it off for a full 5 minutes. This is the correct first step for both interpretations of E03 — it clears transient board faults and is the only reset method that fully discharges the control board's capacitors. Restore power and run a full test cycle before proceeding further.

If E03 clears and the next cycle completes normally, a power event was the cause. Monitor for recurrence over the following days.

Check the water supply and inlet hose (fill-failure models)

Open the cabinet under the sink and confirm the supply shut-off valve is turned fully counter-clockwise (open). Pull the dishwasher out slightly and trace the inlet hose for any kinks or sharp bends — straighten any you find. Push the machine back slowly, ensuring the hose doesn't re-kink as it tucks away behind the unit.

Clean the inlet hose mesh filter (fill-failure models)

Turn off the supply valve, then disconnect the inlet hose at the machine end. Remove the small mesh screen from inside the fitting using needle-nose pliers and rinse it thoroughly under running water, brushing away any mineral crust. Reinstall it firmly and reconnect the hose. Also check the filter at the valve end if accessible. Reopen the supply and run a test cycle.

If E03 clears after cleaning the filter and confirming the hose is kink-free, a flow restriction was the cause. No further action needed — clean the filter every few months to prevent recurrence.

Inspect wiring connections to the control board relay circuit

With the dishwasher fully disconnected from power, access the control board — typically by removing the inner door panel. Check the wiring harness connectors on the board for any that have pulled loose, show signs of corrosion, or have discoloured insulation indicating heat damage. Reseat any loose plugs firmly. Also look at the wiring running from the board toward the heating circuit for chafing or breaks.

Safety note: Only inspect wiring with the power fully disconnected at the breaker and the plug pulled from the wall. The control board operates at mains voltage.

Book a technician for control board / relay diagnosis

If the breaker reset didn't clear E03, the supply and filter are confirmed good (or the tub was filling normally), and wiring connections look sound — the auxiliary relay on the control board itself has failed, or the power module has broader internal damage. Bosch's factory programming restrictions on replacement power modules mean this repair requires a certified technician on virtually all current Bosch models. Bosch's own guidance for E0105 is to contact Bosch Customer Support directly at 1-800-944-2904.

When to Call a Technician

A breaker reset and basic supply checks are the realistic DIY options for E03/E0105. Book a professional repair if:

E03 or E0105 returns after a full 5-minute breaker reset
The tub fills normally but the cycle still stops with E03 — the relay fault interpretation applies and the board needs testing
Supply valve is open, hose is kink-free, and filter is clean, but E03 keeps returning on fill-failure models
Wiring inspection reveals burned, corroded, or damaged connectors at the control board
The code is E0105 specifically — Bosch's own guidance is to call customer support for this code with no DIY step listed
The control board or power module needs replacement — factory-programmed units are not available for self-installation on current Bosch models

Repair Cost Expectations

If You Fix It Yourself

$0–$80

Breaker reset and supply valve checks cost nothing. A replacement water inlet valve for fill-failure models runs $40–$80 as a DIY part if the valve itself is faulty.

Professional Repair

$200–$500

Typical range in the Boston area for control board / power module diagnosis and replacement — parts and labor included. Inlet valve replacement (fill-failure cause) runs $120–$240.

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Frequently Asked Questions

Why does E03 mean different things on different Bosch dishwashers?

Bosch has produced many generations of dishwashers across different regions, and error code assignments are not always consistent across all product lines. On most current models, E03 maps to an auxiliary heater relay fault in the power module — the same family as E01 and E02. On some older or regionally-specific Bosch models, the same code was assigned to a water fill failure. The symptoms tell you which interpretation applies: an empty or barely-filled tub points to fill failure; a machine that ran for several minutes before stopping points to the relay fault.

Are E03 and E0105 the same error?

Yes — E03 is the two-digit display format used on older Bosch models, and E0105 is the four-digit equivalent used on newer HomeConnect-era and Series 8 machines. Both identify the same auxiliary heater relay fault on the main control board. Notably, Bosch's own troubleshooting page for E0105 skips the breaker-reset suggestion it provides for E0106 and E0107, and goes straight to recommending a call to customer support — reflecting how reliably this code points to a board-level hardware fault.

Can I replace the control board myself to fix E03?

On current Bosch models, replacement power modules are factory-programmed with unit-specific calibration data. Installing an off-the-shelf board without the correct programming will result in a dishwasher that does not function. Bosch and most appliance repair professionals strongly recommend a factory-certified technician for any power module replacement on current models.

My dishwasher's tub is empty when E03 shows — what should I check first?

An empty tub alongside E03 strongly suggests your model is using E03 as a water fill failure code rather than a relay fault. The three free checks to do first are: confirm the supply shut-off valve under the sink is fully open, straighten any kinks in the inlet hose, and clean the small mesh filter inside the inlet hose fitting at the machine connection. These three steps resolve the majority of fill-failure E03 cases without any parts or expense.

How much does it cost to fix E03 or E0105?

A breaker reset and supply valve checks cost nothing. A replacement inlet valve (for fill-failure models where the valve is confirmed faulty) runs $40–$80 as a DIY part. Professional repair in the Boston area for control board diagnosis and power module replacement typically runs $200–$500, parts and labor included. Inlet valve replacement by a technician runs $120–$240.