Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA E27 Error Fix: Voltage Supply Dip / Power Surge

Error code E27 on the Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA means: Voltage Supply Dip / Power Surge. The control board has detected a voltage supply anomaly — either a dip below minimum voltage or a power surge. Check the electrical outlet and circuit breaker. Ensure the dishwasher is on a dedicated 15- or 20-amp circuit (not shared with a garbage disposal or other heavy-draw appliance). Check for loose connections at the junction box under the dishwasher. If power surges are common in your area, use a surge protector. Persistent E27 codes may indicate a failing power supply board or main control board.

The most successful fix is "Test and Replace Power Supply or Main Control Board" (hard difficulty, ~90 minutes). Estimated DIY cost: $50-$100. HomeMD has 2 community-ranked fixes for this error.

This error is rated medium severity. It should be addressed soon, but your appliance may still function in a limited capacity.

Yes — the top-ranked community fix ("Test and Replace Power Supply or Main Control Board") is rated hard difficulty and takes about 90 minutes. Tools needed: T20 Torx screwdriver, Multimeter, Needle-nose pliers.

DIY cost: $50-$100. Professional repair typically costs $200-$350. Many homeowners save money by trying the top-ranked community fix first.

The Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA has 8 other known error codes, including: E0 (No Fault Codes Recorded), E1 (Heating Problem), E12 (Calcification / Scale Buildup), E13 (Water Heating Timeout), E14 (Flow Meter / Water Sensor Error), and 3 more.

Error code E27 also appears on 11 other Bosch models: SHE3AR75UC 24 in 100 Series Front Control 50 dBA, SHE53C85N 24 in 300 Series Front Control 46 dBA, SHP65CM5N 24 in 500 Series Pocket Handle 44 dBA, SHP65TL5UC 24 in 500 Series Bar Handle 44 dBA with AutoAir, SHP878ZD5N 24 in 800 Series Pocket Handle 42 dBA, SHPM88Z75N 800 Series Dishwasher, and 5 more. The fix may vary by model, so check each model's specific page for tailored repair steps.