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Bosch E31 Code: Water Level Sensor Malfunction

Quick Answer

Bosch E31 is a pressure switch fault - and the most common cause is a clogged pressure hose, which is a free fix. The small rubber hose (about 1/4 inch diameter) connecting the tub to the pressure switch gets blocked with soap residue. Disconnect both ends, hold it up to light, and clear any blockage. If the hose is clear, do the blow test on the switch itself - you should hear a click and see the multimeter change when you puff air into the port.

Bosch E31 means the pressure switch - the sensor that tells the dishwasher how much water is in the tub - is giving incorrect readings. The most common cause is a clogged pressure chamber tube. The pressure chamber is a small dome connected to the tub by a short rubber hose, and this hose can get blocked with detergent residue. Cleaning the pressure hose and chamber is often a free fix. If the chamber and hose are clear, the pressure switch itself may have failed and needs replacement.

BoschDishwasherSeverity: moderateDifficulty: intermediate80% DIY Success
Time to Fix
30–120 min
Difficulty
intermediate
Parts Cost
$20 – $45
Tools Needed
Multimeter, Pipe cleaner or thin wire
Wrong code?

Not seeing E31 on your display?

Select what your appliance is actually doing and we'll take you to the right guide.

overfill condition detected
E17
no water entering tub
SYMPTOM
flow sensor not detecting water
E07

What Does the E31 Code Mean?

Bosch dishwashers use a pressure-based water level detection system. A small dome (the air trap or pressure chamber) is connected to the outer tub wall. As water fills the tub, it compresses air in this trapped chamber, increasing pressure on a switch. The switch signals the control board at different pressure thresholds. When the pressure hose is blocked with mineral deposits or soap residue, the chamber cannot sense changing water levels accurately, producing E31.

Most Likely Causes

Based on aggregated repair data, here is the probability breakdown for this error code:

Clogged pressure hose between tub and pressure switch40%
Detergent residue blocking the pressure chamber air trap24%
Wiring issue between pressure switch and control board22%
Failed pressure switch (electrical contact wear)14%

Symptoms You May Notice

  • E31 displayed, dishwasher stops at fill or early wash phase
  • Dishwasher overfilling or underfilling before E31 appears
  • E31 with visible appropriate water level in tub
  • Intermittent E31 that clears with reset

Can you reset a Bosch dishwasher to clear the E31 code?

After cleaning the pressure hose or replacing the switch, hold Start/Reset for 5 seconds and run a test cycle to confirm E31 is cleared.

Tools Required for Diagnosis

MultimeterPipe cleaner or thin wireWhite vinegarFlathead screwdriver

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

1

Locate and inspect the pressure hose

The pressure switch is usually mounted on the side wall of the tub interior or near the kick plate area at the front bottom. It has a small rubber hose approximately 1/4 inch in diameter connecting it to an air trap dome on the outer tub wall. Turn off power and water before proceeding. Disconnect the hose from both the switch end and the tub end. Hold the hose up to a light source and look through the length - you should see light through the entire tube. Any dark or opaque area indicates a blockage of mineral scale or soap residue. Pay particular attention to the air trap fitting at the tub end, which collects the most debris.

2

Clean the pressure hose and air trap

3

Blow test on the pressure switch

4

Check wiring to the pressure switch

Replacement Parts

If your diagnostic testing proves the component has failed, you will need a replacement. We recommend OEM parts over aftermarket for water-handling components.

Part Name
Pressure Switch / Water Level Switch00425928 · $20–$45

Repair vs. Replace Calculator

Appliance Age (Years)7 Yrs
Labor Approach
Our Verdict
REPAIR
Estimated Cost: $33 (Parts) vs $650 (New Machine)

Frequently Asked Questions

Where is the pressure sensor on a Bosch dishwasher?
The pressure switch on a Bosch dishwasher is located near the bottom of the tub, typically mounted on the side wall of the inner cabinet or accessible behind the kick plate panel at the front bottom. It is connected to the tub via a thin rubber hose that runs to an air trap dome at the tub base. The switch itself is a small round or rectangular component with 2-3 wires connected to it. On most models it is accessible without fully pulling the dishwasher from the cabinet.
Can I clean the pressure chamber myself to fix E31?
Yes, and cleaning the pressure hose and air trap should be the first repair step before buying any parts. The procedure requires no special tools - just a pipe cleaner, white vinegar, and about 45 minutes. Disconnect power and water, remove the hose from the switch and tub ends, soak it in vinegar for 30 minutes, flush with water, and confirm air flows freely through it before reinstalling. This free fix resolves E31 in a large percentage of cases, particularly on dishwashers more than 5 years old.
I have E31 and the dishwasher won't fill - are they related?
Yes, they are related. If the pressure switch reads no water (because its hose is blocked), the control board may interpret this as the tub being empty even when water is present, preventing it from advancing through the fill phase. Alternatively, if the switch is stuck reading a full tub, the fill valve will not open because the board thinks sufficient water is already present. Either way, cleaning the pressure hose is the correct first diagnostic step before chasing a fill valve problem.
How do I do the blow test on a Bosch pressure switch?
Disconnect the rubber hose from the switch inlet port. Set a multimeter to continuity mode. Place the probes on the switch terminals (the common pin and the normally-closed pin). Blow a short firm puff of air directly into the switch inlet port - the switch should make an audible click and the multimeter continuity reading should change from closed to open. Release and the circuit should return to closed with another click. If no click occurs or the multimeter reading does not change, the switch diaphragm or contacts have failed and the switch needs replacement.
How often should the pressure hose be cleaned on a Bosch dishwasher?
Bosch does not publish a specific cleaning interval for the pressure hose, but in hard-water areas, a cleaning every 3-4 years is a practical preventive measure. The hose is most likely to clog if you use powdered detergent (which leaves more residue than gel or pod detergents) or if your water supply has high mineral content (above 120 mg/L calcium carbonate). If you receive an E31 code and cleaning resolves it, that is a signal to add the procedure to your maintenance schedule going forward.

Related Bosch Dishwasher Error Codes

Code: E17Bosch E17 Error: Overfill Protection ActivatedCode: SYMPTOMBosch Dishwasher Not Filling with Water: Full WalkthroughCode: E07Bosch E07 Code: Flow Sensor Problem Explained

Same Fix Works on These Brands

Bosch shares the same hardware platform with these brands. The diagnosis and repair steps are identical.

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Models Known to Experience E31 Errors

This repair applies to most Bosch dishwashers with this error code. Common model numbers include:

SHPM88Z75N, SHPM88Z55N, SHPK7ZL55N, SHE3AR75UC, SHEM63W55N, SHPM65Z55N, SHE3AR72UC, SHDF78Z55N, SHEM78ZH5N, SHPM98Z75N

Last verified for technical accuracy on March 14, 2026