Bosch Dishwasher E27 Error — Water Supply Insufficient / Inlet Valve Fault Fix

Common Symptoms

• E27 error code displayed during or at the start of a wash cycle
• Dishwasher fills with little or no water — tub sounds nearly empty during wash
• Cycle starts but stops early with E27 — not enough water to proceed
• Unusually long fill time before E27 triggers
• Dishes come out dirty because there was not enough water to wash them

Most Likely Causes

1. 1

   Water Supply Valve Partially Closed (Most Common — Free Fix)

   The water supply shutoff valve under the sink or behind the dishwasher panel is the first thing to check. If it was bumped during cleaning, plumbing work, or cabinet reorganization and is only partially open, the dishwasher won't fill fast enough and E27 triggers. Simply turning the valve fully counterclockwise (open) resolves E27 immediately.

2. 2

   Kinked or Restricted Inlet Hose

   The braided inlet hose that runs from the supply valve to the dishwasher's water inlet valve can become kinked if the dishwasher was pushed back into its bay at an angle. A kink reduces water flow significantly. In some cases, hard water mineral deposits partially obstruct the hose over time, especially at the inlet screen where the hose connects to the valve.

3. 3

   Water Inlet Valve Solenoid Failure

   The water inlet valve is a solenoid-controlled valve that opens to fill the dishwasher and closes to stop filling. The solenoid coil can fail electrically (open or shorted winding) or the valve's mechanical components can stick due to mineral scale deposits. A failed inlet valve solenoid must be replaced — testing the solenoid resistance with a multimeter confirms the fault. A healthy Bosch inlet valve solenoid reads 200–500Ω.

4. 4

   AquaStop Float Switch Fault

   Bosch dishwashers equipped with AquaStop use a float switch in the base pan that also interacts with the water supply circuit. If the float switch is stuck in the tripped position (as if the base pan is flooded), the control board will not open the inlet valve, causing E27. This is distinct from E15: with E27, there may be no visible water in the base pan, but the switch is sending a false signal.

5. 5

   Flow Meter Malfunction

   Bosch 500 and 800 series dishwashers use a flow meter (turbine sensor) to measure how much water enters the tub during the fill cycle. A failed or stuck flow meter sends no signal or a faulty reading to the control board, which interprets this as insufficient water flow and throws E27, even if water is actually flowing normally.

Quick DIY Checks

1. 1SAFETY FIRST — Unplug the dishwasher or turn off the dedicated circuit breaker before any internal inspection. If testing the water supply valve (which is outside the dishwasher), power off is still recommended to avoid triggering an unwanted fill cycle.
2. 2Check the water supply valve: locate the dishwasher's water supply shutoff valve — typically a standard angle stop valve under the kitchen sink or in the cabinet adjacent to the dishwasher. Turn it fully counterclockwise to ensure it is completely open. On some installations, the valve has only a 90-degree quarter-turn range — the handle should be parallel to the pipe (open) not perpendicular (closed). If the valve was partially closed, open it fully, restore power, and run a test cycle.
3. 3Inspect the inlet hose for kinks: pull the dishwasher carefully forward from its bay a few inches. Trace the braided inlet hose from the supply valve to the inlet valve on the dishwasher. Look for kinks, sharp bends, or sections where the hose is pinched by the dishwasher body or cabinet frame. Straighten any kinks. Also check the mesh inlet screen where the hose connects to the dishwasher's inlet valve fitting — a clogged screen restricts flow enough to trigger E27. Use needle-nose pliers to unscrew the hose fitting, pull out the mesh screen, rinse it under running water, and reinstall.

1. 4Test the water inlet valve solenoid resistance: disconnect power and access the water inlet valve — it is typically at the bottom left side of the dishwasher behind the lower access panel (two screws). Disconnect the wiring harness from the inlet valve solenoid terminals. Set your multimeter to Ω mode and probe the two solenoid terminals. A healthy Bosch inlet valve solenoid reads 200–500Ω. A reading outside this range — 0Ω (shorted) or OL/infinite (open winding) — means the valve has failed and must be replaced. Match the replacement to your model number and FD date code.
2. 5Test the AquaStop float switch: the AquaStop float switch is located in the dishwasher base pan under the unit. Remove the lower access panel. The float switch has a two-wire connector. Disconnect the connector and set your multimeter to continuity mode. With the float resting in its normal (down) position, the switch should show continuity (closed circuit). If it reads open, the switch is either stuck or has failed — inspect the float assembly for debris preventing it from sitting down. Clean around the float and retest.
3. 6Check the flow meter (800 series / SHPM88Z75N): the flow meter is a turbine sensor in-line with the water inlet path, typically located near the inlet valve. It has a two- or three-wire connector. With power disconnected, check that the turbine spins freely by blowing gently into the water port — it should spin with very little resistance. If the turbine is stuck or corroded with mineral scale, flush it with a descaling solution or replace the flow meter assembly. Flow meter replacement requires accessing the water inlet assembly under the dishwasher.
4. 7Replace the inlet valve if tests show failure: if the solenoid resistance tested out of range, order a replacement inlet valve for your specific model. For SHPM88Z75N and SHX5AV55UC, verify the part number against the model/FD label inside the door frame. Installation: disconnect power and water supply, place a towel under the valve, disconnect the inlet hose, wiring harness, and any internal water tubing, remove the mounting screw(s), install the new valve in reverse order. Run two fill cycles to confirm E27 is resolved and check for leaks.

Repair vs Replace

Recommended Tools & Parts

• Bosch Dishwasher Water Inlet Valve

  Replacement water inlet valve solenoid assembly for Bosch 300/500/800 series dishwashers. Required when the solenoid resistance tests outside the 200–500Ω range or when the valve fails to open or close properly. Verify the part number against your model's FD date code label inside the door frame.

  $40–$85

  Buy on Amazon →

• Bosch Dishwasher Flow Meter / Turbine Sensor

  Replacement flow meter turbine sensor for Bosch 500 and 800 series dishwashers (SHPM88Z75N, SHEM78ZH5N). Required when E27 persists after confirming the inlet valve and supply are good and the flow meter turbine is stuck or sending no signal to the control board.

  $25–$55

  Buy on Amazon →

• Bosch Dishwasher AquaStop Inlet Hose Assembly

  Complete AquaStop water supply hose with integrated solenoid shutoff. Replacement required if the inlet hose has developed an internal leak, the AquaStop solenoid has failed open (preventing fill), or the hose connection fitting is damaged. Model-specific.

  $45–$90

  Buy on Amazon →

Links are Amazon affiliate links (tag: fixitfastai-20). Prices are estimates.

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