Error code E24 or E25 indicates a Drain Water Evacuation Failure on Bosch dishwashers. During the initial 2-minute cycle start or between wash and rinse phases, the control board energizes the high-efficiency BLDC brushless drain pump. If water is not evacuated within the programmed deadline—or if the micro-controller senses electrical back-EMF spikes indicating impeller resistance—the machine halts and sounds an alarm chime.
The #1 Root Cause: The Missing “Impeller Cover Click”
Unlike other dishwasher brands, Bosch uses a precision hydro-dynamic impeller cavity capped by a small white curved plastic pump cover shield. If this cover is even 1 millimeter loose, water will recirculate in a vortex inside the sump well rather than creating the vacuum required to pump water out through the discharge hose.
Step 1: Removing and Clearing the Impeller Cavity
- Open the dishwasher door and remove the lower dish rack.
- Turn the central cylindrical stainless steel filter assembly counter-clockwise and lift it out of the sump basin.
- Use a sponge or towel to soak out all standing water until the plastic sump bowl is empty.
- Locate the white curved plastic clip cover positioned at the 10 o’clock position inside the sump well.
- Insert the handle of a metal teaspoon or a blunt knife beneath the curved plastic lip and gently pry it upward until it pops off.
- Put on a disposable work glove and carefully check the small white plastic impeller blades beneath. Broken glass shards, lemon seeds, twist-ties, and olive pits frequently wedge between the impeller blades and the plastic housing.
- Rotate the impeller blades with your finger. They should rotate with a rhythmic, springy magnetic resistance, but must not jam.
- Check the black rubber non-return check valve flap located behind the filter opening; ensure it hinges freely and is not stuck closed.
- CRITICAL STEP: Place the white plastic cover back over the impeller. Press down firmly on the raised notch until you hear and feel a distinct, loud CLICK. If it does not click, E24/E25 will return immediately!
Step 2: Multimeter Resistance Test on Bosch BLDC Drain Pump (85–95 Ω)
Modern Bosch dishwashers utilize an advanced 3-phase BLDC (Brushless Direct Current) synchronous drain pump motor. If the impeller cavity is totally unobstructed but the pump hums softly and errors out, test the motor coil phases with a multimeter.
| BLDC Pump Terminal Test Points | Expected OEM Reading | Diagnostic Interpretation |
|---|---|---|
| Pin 1 to Pin 2 | 85 Ω to 95 Ω | PASS: Phase winding healthy. |
| Pin 2 to Pin 3 | 85 Ω to 95 Ω | PASS: Phase winding healthy. |
| Pin 1 to Pin 3 | 85 Ω to 95 Ω | PASS: Phase winding healthy (All 3 phases must match within ±2 Ω). |
| Any Pin Reading Infinite (O.L.) or Under 20 Ω | Infinite or 0 Ω | FAIL: Phase winding burnt out or shorted. Replace BLDC pump #00631200. |
OEM Replacement Part Information
Bosch Synchronous BLDC Drain Pump Assembly
OEM Part Number: 00631200 (Replaces 00642239, 00611332, AP4354228, PS8729906)
Compatibility: Fits all Bosch 300, 500, 800 Series, SilencePlus, Benchmark, and Thermador dishwashers.
Installation Time: 25 minutes from the lower front toe-kick access area.
Connected Diagnostic Procedures & Next Steps
A clogged sump impeller or dislodged shield can cause water seepage directly into the base pan. Cross-reference these connected solutions:
Frequently Asked Questions
Why does E24 happen after installing a brand-new garbage disposal?
When a new garbage disposal is installed, the solid plastic knockout plug inside the disposal’s dishwasher drain inlet nipple MUST be punched out with a screwdriver and hammer. If the plug was left in, water cannot enter the disposal, triggering E24 within 2 minutes.
Why did E24 clear when I opened and closed the door at the 1-minute mark?
This common Internet “trick” forces the main PCB to skip the initial pump check algorithm and jump directly to wash circulation. However, this is only a temporary workaround; when the machine attempts to drain before the rinse cycle, E24 will recur until the physical restriction is eliminated.
