Category: Dishwasher

1. Clogged Filter Assembly (Most Common)

Bosch dishwashers use a two-part filter — a cylindrical micro-filter and a flat mesh plate — that traps food debris. When either becomes blocked, water has nowhere to go and pools at the bottom of the tub.

1. Cancel the current cycle and open the door. Scoop or blot out standing water with a sponge or turkey baster.
2. Locate the filter assembly on the floor of the dishwasher tub, near the back of the spray arm.
3. Turn the cylindrical filter counter-clockwise about a quarter-turn and lift it straight out.
4. Lift the flat mesh filter up and out as well.
5. Rinse both pieces under warm running water. Use a soft brush (an old toothbrush works well) to scrub away grease and debris. Do not use abrasive pads.
6. Inspect the sump cavity beneath where the filters sat and remove any visible debris by hand.
7. Reinstall the flat filter first, then insert and lock the cylindrical filter by turning it clockwise until it clicks.
8. Run a short rinse cycle to confirm the machine drains fully.

2. Blocked or Kinked Drain Hose

The drain hose carries water from the pump to the sink drain or garbage disposal. A kink, food-debris clog, or improper installation can create a blockage that prevents draining entirely.

1. Pull the dishwasher slightly forward (after shutting off power at the breaker) to access the drain hose at the rear of the unit.
2. Visually inspect the entire length of the hose for kinks or sharp bends. Straighten any you find.
3. Disconnect the hose at the sink drain or garbage disposal end (have a towel ready — residual water will spill).
4. Blow through the hose or run water through it to confirm it is clear. If blocked, use a long flexible brush or gently push a garden hose through to dislodge debris.
5. Confirm the hose has a high loop — the hose should rise to the underside of the counter before descending to the drain connection. This prevents backflow.
6. Reconnect the hose securely with a hose clamp, restore power, and run a drain cycle.

3. Garbage Disposal Knockout Plug Not Removed

If you recently installed a new garbage disposal and connected the dishwasher drain hose to it, a plastic knockout plug inside the disposal inlet may still be in place, completely blocking drainage.

1. Disconnect the drain hose from the disposal inlet.
2. Look inside the disposal inlet port with a flashlight. If you see a solid plastic disc blocking the opening, the knockout plug was never removed.
3. Insert a flathead screwdriver into the port and tap firmly with a hammer to punch the plug into the disposal body.
4. Remove the disposal from its mount and shake it over a trash can to retrieve the loose plug — leaving it inside can damage the disposal.
5. Reattach the drain hose and run a test drain cycle.

4. Faulty or Obstructed Drain Pump

The drain pump uses an impeller to actively push water out of the sump through the drain hose. A small piece of glass, a broken dish fragment, or a failed pump motor will stop it from spinning, leaving water standing in the tub.

1. Shut off power at the breaker and remove all standing water from the tub.
2. Remove the filter assembly (see Cause 1) to expose the pump cover in the sump.
3. On most Bosch models, unclip or unscrew the pump cover to reveal the impeller. Rotate the impeller by hand — it should turn freely. If it is stiff, jammed, or you hear grinding, there is foreign material or bearing damage.
4. Use needle-nose pliers or tweezers to remove any visible debris (glass shards, seeds, twist-ties) from around the impeller.
5. If the impeller spins freely but the pump still does not run, use a multimeter to test the pump motor for continuity. A reading of OL (open/no continuity) indicates a failed motor.
6. Replace the drain pump if it fails the continuity test or shows visible damage.

5. Blocked Air Gap or Standpipe

Some Bosch dishwasher installations include a countertop air gap fitting that prevents drain backflow. If the air gap becomes clogged with grease and debris, drainage backs up into the dishwasher.

1. Locate the air gap — it is the small cylindrical cap on the countertop or sink deck near the faucet.
2. Unscrew or pop off the decorative cap, then remove the inner plastic cap beneath it.
3. Clean out any slimy buildup or debris from both the air gap body and the two hose connections underneath the counter using a small brush.
4. Reassemble the air gap and run a drain cycle to verify the fix.
5. If no air gap is present, check the standpipe height — the drain hose connection point should be no higher than 32 inches from the floor for proper drainage.

6. Failed Door Latch or Control Board Interrupting the Drain Cycle

Bosch dishwashers will not complete a drain cycle if the control board does not receive a proper door-closed signal, or if the control board itself has failed and is not sending power to the drain pump.

1. Check that the door closes firmly and latches with a click. Inspect the door latch strike for cracks or misalignment.
2. Run a diagnostic cycle: on most Bosch models, press and hold the Start button for 3–5 seconds to initiate a drain-only sequence. If the pump activates, the board is likely functional.
3. Inspect the control board (accessible by removing the inner door panel) for burnt spots, bulging capacitors, or signs of moisture damage.
4. If the door latch is visibly broken, replace it and test again before condemning the board.
5. If the control board is damaged, consider the repair-versus-replace cost before ordering a new board, as boards are the most expensive component.

Frequently asked questions

User Manuals: https://www.bosch-home.com/us/owner-support/owner-manuals