Bosch Dishwasher Error Code E31 — Flow Meter Malfunction

What Does This Error Mean?

E31 means the flow meter inside your Bosch dishwasher is not measuring water correctly. The flow meter counts how much water has entered the machine — it's like a tiny water meter inside the dishwasher. When it gives readings that are too far out of expected range, the control board triggers E31 and stops the cycle. This can happen because the flow meter itself has failed, or because debris is interfering with its spinning measurement wheel.

Affected Models

SMS46GI01A
SMS68MI02G
SMV68IX00E
SPV6ZMX23E
SMS8YCI01E
Bosch dishwashers with turbine-style flow meters (most models)

Common Causes

Debris or mineral scale lodged in the flow meter impeller, preventing it from spinning freely
Failed flow meter sensor that can no longer count impeller rotations accurately
Very low water pressure causing the impeller to spin too slowly for accurate measurement
Air pocket in the water supply line interrupting the flow meter reading
Wiring connector to the flow meter is loose or corroded

How to Fix It

Run a full power reset first. Unplug the dishwasher for 10 minutes, then restore power and run a test cycle. E31 caused by a temporary air pocket or sensor glitch often clears with a full reset and fresh cycle.

If you recently had water supply work done or the water was shut off for a period, an air pocket in the line can cause a one-time flow meter error.
Check your water pressure. Very low pressure causes the flow meter impeller to spin too slowly, which the dishwasher interprets as a fault. Test pressure at a nearby tap — water should flow strongly, not in a trickle. If pressure seems low, investigate the supply valve and home pressure.

Bosch flow meters are calibrated for a specific pressure range. Persistent low pressure will cause repeated E31 codes.
Access the flow meter. It's usually located on the water inlet path in the sump area at the bottom of the dishwasher. You'll need to remove the lower rack, spray arm, and filter to see it. The flow meter looks like a small cylinder with a visible impeller wheel inside.

Take photos as you disassemble — the sump area has multiple components and it's easy to lose track of where things go.
Inspect the flow meter impeller for debris. With the meter disconnected from the water path, spin the impeller wheel gently with your finger. It should spin freely and easily. If it's stiff, stuck, or there's visible grit inside, clean it with warm water and a soft brush or replace the meter.

Limescale deposits are a common cause of sticky impellers in hard water areas. A 30-minute soak in white vinegar often frees a scaled impeller.
Check the flow meter's wiring connector for corrosion or looseness. A connector that's partially disconnected causes the control board to receive no signal from the meter, which it interprets as a failure. Clean and firmly reseat the connector.

If cleaning the impeller and checking connections doesn't help, replace the flow meter as a unit — they're inexpensive and the full meter assembly is easier to swap than trying to repair individual components.

When to Call a Professional

Flow meter replacement requires accessing the sump area of the dishwasher. A replacement Bosch flow meter typically costs $20-$45 for the part. This is a moderately advanced DIY repair. A technician charges $130-$250 including parts and labor.

Frequently Asked Questions

Is E31 similar to E14 on Bosch dishwashers?

They're related — both involve the flow meter. E14 typically triggers when the flow meter's reading deviates from expected during a fill cycle. E31 indicates a more general flow meter malfunction or out-of-range measurement condition. The troubleshooting steps are nearly identical: check the impeller, inspect connections, and consider replacement.

My Bosch dishwasher shows E31 every few weeks but then works again. What causes this?

Intermittent E31 often points to a partial scale buildup on the impeller that causes occasional sticking. The impeller frees itself with water flow, so the machine works for a while, then sticks again. Cleaning the flow meter properly, or running a descaling cycle monthly, usually prevents the pattern from repeating.

Can I descale my Bosch dishwasher to prevent E31?

Yes — regular descaling prevents mineral buildup that can clog the flow meter impeller. Run an empty cycle with a dishwasher descaler (or 200ml of white vinegar in the base of the tub) once a month in hard water areas. Bosch also sells its own dishwasher cleaner specifically designed to remove scale from internal components.