Bosch Dishwasher E24 Error — Drain Blocked or Kinked Hose Fix (300, 500 & 800 Series)

Common Symptoms

• E24 error code on Bosch display or red LED projection at base of door
• Standing water at the bottom of the dishwasher tub after a cycle
• Dishwasher stops mid-cycle and will not continue
• Gurgling or straining sounds from the drain area during drain phase
• Slow drainage — water drains but takes much longer than normal
• Dishes still wet and water pooling after cycle completes

Most Likely Causes

1. 1

   Clogged Filter Assembly (Most Common — Free Fix)

   Bosch dishwashers have a two-part filter at the center bottom of the tub: a cylindrical fine-mesh filter (quarter-turn removal) and a flat coarse pre-filter beneath it. Food particles, grease, and debris accumulate here and restrict drain flow. Even partial clogging triggers E24 because the pump cannot move water fast enough. Bosch recommends cleaning the filter every 1–2 months, but most owners never clean it. This is the first thing to check on every E24 code.

2. 2

   Kinked Drain Hose Behind the Unit

   The drain hose runs from the dishwasher pump through the cabinet floor to the sink drain or garbage disposal. When the dishwasher is pushed back into its bay after installation or service, the hose can develop kinks at tight bend points behind the unit. A kinked hose severely restricts drain flow and causes E24. The hose must also have a high loop — routed up to at least 20 inches from the floor before dropping to the connection point — to prevent siphoning backflow.

3. 3

   Drain Hose Inserted Too Deep into Standpipe

   If the drain hose is inserted more than 4 inches into a sink standpipe or drain tailpiece, it creates an airtight seal that blocks drainage (water can't flow out because there's no air gap to break the vacuum). This is a very common installation mistake on Bosch 300 and 500 series dishwashers and is one of the most frequently missed E24 causes.

4. 4

   Blocked Garbage Disposal Connection

   If the dishwasher drains into a garbage disposal, the knockout plug inside the disposal inlet must be removed during installation. A missing knockout removal means zero drainage. Even if the knockout was removed, debris from the disposal can clog the drain connection over time. Run the disposal for 30 seconds before every dishwasher load to prevent this.

5. 5

   Clogged Air Gap on Sink

   Many installations include a drain air gap — a chrome fitting mounted on the sink or countertop — between the dishwasher and the disposal or drain. Food debris accumulates inside the air gap body and can completely block drain flow, causing E24. The air gap is frequently overlooked during E24 diagnosis because it's not on the dishwasher itself.

6. 6

   Failed Drain Pump Check Valve

   A rubber check valve inside the drain pump housing prevents drained water from flowing back into the tub. If this valve fails in the closed position, the pump can move water during the drain cycle but the water returns to the tub when the pump stops. This creates a cycle where the pump runs but E24 persists — drain water never fully clears the system.

Quick DIY Checks

1. 1Clean the filter assembly: this is the first step for every E24 code. Remove the lower dish rack. At the center bottom of the tub, locate the cylindrical filter — grip the raised handle and rotate counterclockwise approximately a quarter-turn, then lift it straight out. Beneath it is the flat coarse pre-filter mesh — lift this out as well. Rinse both filters under hot running water. Use a soft toothbrush on the cylindrical fine-mesh filter to clear grease and food buildup — a dish soap soak for 5 minutes loosens stubborn grease. Reinstall: place the flat mesh filter first, then seat the cylindrical filter and rotate clockwise until it locks with a click. A loose filter is as bad as a dirty one — always confirm it's locked.
2. 2Check drain hose routing and kinks: pull the dishwasher forward from its cabinet bay (after turning off the water supply valve under the sink). Inspect the drain hose running from the pump outlet (lower left rear of the dishwasher) to its sink connection. The hose must not have any kinks or sharp bends — straighten any kinks by hand. Verify the hose has a high loop, routing up to the underside of the counter (at least 20 inches from the floor) before dropping to the drain connection. If there is no high loop, reroute the hose and secure it with a drain hose clip or zip tie to the underside of the counter.
3. 3Check drain hose insertion depth: at the sink connection point, check how far the drain hose is inserted into the standpipe, drain tailpiece, or garbage disposal inlet. It should not go deeper than 4 inches into the pipe. If it's inserted too far, pull it back and secure it at the correct depth with a hose clamp. The opening of the drain hose and the drain connection must allow air to enter around the hose to prevent a vacuum seal.

1. 4Check the garbage disposal connection: if the dishwasher drain hose connects to a garbage disposal, run the disposal for 30 seconds to clear any debris at the inlet. If this is a new disposal installation, confirm the knockout plug was removed — look into the disposal inlet opening with a flashlight; you should see an open passage. If the knockout plug is still in place, use a screwdriver and hammer to knock it out, then retrieve it from inside the disposal before running the unit.
2. 5Inspect the air gap (if installed): look on the sink or countertop for the air gap — it's a small chrome cap, usually near the faucet. Unscrew or pull off the chrome cap. Inside is a plastic body with two chambers. Remove any debris from the gap body — a toothpick or small brush works well. Rinse with water. If the air gap cap has been removed and there's no air gap in the installation, ensure the drain hose high loop is in place as a substitute anti-backflow measure.
3. 6Test drain pump operation: manually drain any standing water from the tub using towels and a bowl to reduce load on the pump. Reinstall the filter assembly. Restore power and run a drain-only cycle — on Bosch 300/500/800 series, press and hold the Start/Cancel button for 3 seconds to initiate a drain cycle. Listen carefully: you should hear the pump motor running as a steady hum and feel vibration at the lower front panel. If the pump hums but water doesn't move, proceed to check for pump impeller blockage (see the E25 article). If the pump is silent, test pump motor continuity with a multimeter (typical Bosch drain pump motor resistance: 100–200Ω).
4. 7Reset and verify: after completing the above checks, restore full power, close the door firmly, and run a short rinse-only cycle. Monitor the drain phase — water should drain within 90 seconds and the cycle should complete without E24. If E24 persists after cleaning the filter and verifying hose routing, the drain pump or check valve likely needs replacement. Part 12014980 covers most Bosch 500 and 800 series models (SHPM88Z75N, SHPM65Z55N, SHEM63W55N).

Repair vs Replace

Recommended Tools & Parts

• Bosch Dishwasher Drain Pump — Part 12014980

  Replacement drain pump motor for Bosch dishwashers. Part 12014980 fits many 500 and 800 series models (SHPM88Z75N, SHPM65Z55N, SHEM63W55N). Required when E24 persists after filter cleaning, hose inspection, and all external checks are clear. Verify model compatibility before ordering.

  $40–$80

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• Bosch Dishwasher Filter Set (Cylindrical + Flat Mesh)

  Replacement two-part filter kit for Bosch dishwashers. If the existing filter mesh is torn or deformed after years of use, replacement prevents recurring E24. Monthly cleaning of the original filter avoids this expense entirely.

  $20–$45

  Buy on Amazon →

• Universal Dishwasher Drain Hose High Loop Clip

  Mounting clip to secure the drain hose in a proper high loop under the counter. Required if the existing installation lacks a high loop — missing high loop is a direct cause of E24 from siphon backflow. Universal fit for Bosch and other dishwasher brands.

  $8–$15

  Buy on Amazon →

• Dishwasher Drain Hose Replacement (Universal 6 ft)

  Replacement drain hose if the original hose has developed a permanent kink, crack, or has hardened with age. Universal 6-ft drain hose fits most dishwashers including Bosch 300, 500, and 800 series with standard 5/8-inch connections.

  $12–$25

  Buy on Amazon →

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

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