Bosch SHXM78W55N (800 Series with MyWay) – E22 error (filter clog) Repair Guide

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Model: Bosch SHXM78W55N (800 Series with MyWay)
Brand: Bosch
Model Number: SHXM78W55N

🔍 Problem Description

Clean all filters thoroughly; check sump area; verify drain pump

📋 What You’ll Need

  • Filter assembly
  • Cleaning tools

    • 🔧 Step-by-Step Repair Instructions

      🔧 Step 1: Remove and clean all filters thoroughly

      1. Open the dishwasher door completely until it rests horizontally.
      2. Pull out the lower dish rack entirely and set it aside.
      3. Locate the cylindrical micro-filter assembly in the center of the dishwasher floor—it’s approximately 4 inches in diameter with a metal mesh screen visible on top.
      4. Grasp the micro-filter by its rim and turn it counterclockwise approximately 90 degrees (one quarter turn) until it stops.
      5. Lift the micro-filter straight up and out—it’s approximately 6 inches tall when fully removed.
      6. Look directly beneath where the micro-filter was—you’ll see a flat, circular fine filter with small perforations, approximately 5 inches in diameter.
      7. Grip the fine filter’s plastic tab located at the front edge.
      8. Lift the fine filter straight up and out of its recess.
      9. Identify the larger stainless steel coarse filter surrounding the fine filter opening—it’s a flat, rectangular frame measuring approximately 10 inches by 8 inches.
      10. Lift the coarse filter straight up from the front edge—no turning required.
      11. Hold each filter under running hot water (120-140°F).
      12. Use a soft-bristle nylon brush to scrub all surfaces, working from the inside to the outside on cylindrical surfaces.
      13. For the micro-filter mesh, scrub both the interior and exterior mesh surfaces using circular motions.
      14. Inspect each filter under good light—all perforations should be completely clear with no food particles, grease film, or mineral deposits visible.
      15. For stubborn residue, soak filters in a solution of 2 cups white vinegar mixed with 2 cups warm water for 15 minutes, then scrub again.

      🛠️ Step 2: Clean sump area of debris

      1. Locate the circular filter assembly in the center bottom of the dishwasher tub – it’s approximately 5 inches in diameter with a cylindrical mesh screen sitting inside a round housing.
      2. Grip the cylindrical mesh filter and rotate it counterclockwise one-quarter turn (90 degrees) until it unlocks.
      3. Pull the mesh filter straight up and out of the sump housing.
      4. Locate the flat circular filter plate beneath where you just removed the mesh filter – this is approximately 4 inches in diameter with perforations.
      5. Lift the flat filter plate straight up to remove it from the sump well.
      6. Look into the now-exposed sump area – you’ll see a white or gray plastic chamber approximately 3 inches deep with a small pump impeller visible at the bottom center.
      7. Use your fingers to remove any visible food particles, broken glass, labels, bones, toothpicks, or other debris from the sump chamber.
      8. Check around the perimeter of the sump opening where it meets the stainless steel tub floor – debris often collects in this corner seam.
      9. Wipe the entire sump chamber interior with a damp cloth or paper towel, reaching down to the impeller area at the bottom.
      10. Inspect the small openings around the pump impeller at the sump bottom – use a toothpick or small brush to dislodge any debris blocking these holes.
      11. Run your finger around the circular lip where the flat filter plate sits to remove any accumulated slime or debris from this sealing surface.
      12. Rinse both the mesh filter and flat filter plate under running tap water, removing all food particles and buildup.
      13. Verify the sump chamber is completely clear by visual inspection – you should see clean white/gray plastic surfaces and unobstructed openings around the impeller.

      ⚙️ Step 3: Verify drain pump operation

      1. Locate the drain pump on the lower left side of the dishwasher base, approximately 4 inches from the left edge and 3 inches back from the front panel.
      2. Identify the white wire connector attached to the drain pump motor—it has 2 wires (black and white) in a rectangular housing measuring approximately 0.5 inches wide.
      3. Press the release tab on top of the white connector with your index finger while pulling the connector straight away from the pump to disconnect it.
      4. Set your multimeter to the ohms (Ί) setting at the 200-ohm range.
      5. Touch the multimeter’s red probe to one of the two exposed metal terminals inside the pump’s connector socket and the black probe to the other terminal.
      6. Read the resistance value—you should see between 180-220 ohms, indicating the pump motor winding is intact; a reading of “OL” (overload) or infinite resistance means the motor is burned out and requires replacement (Bosch part number 00651956).
      7. Switch your multimeter to continuity mode (often marked with a speaker/sound symbol).
      8. Touch one probe to either pump terminal and the other probe to the metal pump housing—the multimeter should NOT beep or show continuity; if it does, the motor is shorted to ground and must be replaced.
      9. Reconnect the white wire connector to the pump by aligning the connector with the pump terminals and pushing firmly until you hear and feel a distinct click.
      10. Rotate the pump impeller by reaching underneath the pump housing and turning the circular impeller blades clockwise with your fingers—it should rotate freely with slight resistance; grinding, clicking, or complete binding indicates mechanical failure.
      11. Check for debris by looking into the pump inlet opening (circular port on the pump body’s right side, approximately 1.5 inches in diameter) using a flashlight—remove any visible food particles, glass shards, or foreign objects with needle-nose pliers.

      🔩 Step 4: Inspect filter housing

      1. Locate the cylindrical filter housing in the bottom center of the dishwasher tub, directly below where the lower spray arm was positioned.
      2. Examine the circular housing rim for cracks, starting at the 12 o’clock position and working clockwise around the entire 8-inch diameter perimeter.
      3. Run your index finger along the inside edge of the housing where the filter basket sits—feel for any rough spots, chips, or buildup that measure more than 1/16 inch in height.
      4. Check the central mesh screen at the bottom of the housing for holes larger than the original 1mm perforations by holding a flashlight underneath and looking for irregular bright spots.
      5. Inspect the three small drain holes positioned at 120-degree intervals around the housing base (4 o’clock, 8 o’clock, and 12 o’clock positions)—each hole should be 3mm in diameter and completely clear.
      6. Insert a straightened paper clip into each drain hole to verify they’re unobstructed; the clip should pass through freely for at least 1/2 inch depth.
      7. Look for white or brown mineral deposits on the housing walls—scrape any buildup thicker than 1/8 inch using a plastic putty knife held at a 45-degree angle.
      8. Examine the rubber gasket seal (if present) around the top rim of the housing—press it with your thumb to verify it’s still pliable and returns to its original shape within 2 seconds.
      9. Check for the small plastic baffle tab located at the 3 o’clock position on the housing rim—verify it’s not cracked or missing, as it directs water flow.
      10. Wipe the entire housing interior with a cloth dampened with white vinegar to remove any remaining residue or film, ensuring the stainless steel surface appears uniformly silver without cloudy spots.

      📋 Step 5: Replace filters if damaged

      1. Grasp the cylindrical micro-filter assembly located in the center of the dishwasher floor and turn it counterclockwise 90 degrees.
      2. Lift the micro-filter straight up and out of the circular housing—it will rise approximately 3 inches.
      3. Inspect the fine mesh screen for tears, holes, or permanent staining that restricts water flow.
      4. If damaged, obtain replacement micro-filter part number 00435650 (original equipment) or 00170740 (alternate).
      5. Insert the new micro-filter into the circular housing, aligning the two molded tabs on the filter base with the matching slots in the housing.
      6. Push down until the filter sits flush with the dishwasher floor, then rotate clockwise 90 degrees—you’ll feel it lock into place with a firm stop.
      7. Locate the large circular coarse filter surrounding the micro-filter assembly.
      8. Lift the coarse filter straight up—no twisting required—removing it from the 4 locating pins on the dishwasher floor.
      9. Examine the plastic mesh for cracks, broken ribs, or warped sections that prevent proper seating.
      10. If replacement is needed, order part number 00427903.
      11. Position the new coarse filter over the 4 circular pins, aligning the semicircular cutout at the front with the corresponding tub shape.
      12. Press down evenly around the entire perimeter until the filter rests flat against the dishwasher floor—all 4 pins should protrude through the corresponding holes in the filter base.
      13. Run your hand across both installed filters—they should sit completely level with no raised edges or gaps exceeding 1/16 inch.
      14. Fill the tub with 2 cups of water and verify no leakage occurs around the filter assembly base within 30 seconds.

      🛒 Recommended Products

      Here are the recommended products for this repair: