Bosch Dishwasher E20 Error Code Explained: Meaning, Causes & Fixes

 
Error Code Meaning
 
The E20 error code on a Bosch dishwasher indicates that the machine’s internal safety system has detected the presence of water in an area where it should not be. This error is generated by a sensor located in the base of the appliance that continuously monitors for any signs of leakage or water accumulation. When water is detected in this area, the sensor communicates with the control board, prompting the display of the E20 error code as a precautionary measure.

• This sensor is part of a built-in leak detection mechanism designed to safeguard the dishwasher from potential water damage.
• Its primary role is to prevent issues such as electrical short circuits or corrosion by stopping the dishwasher’s normal operation when unwanted water is found.
• The appearance of the E20 code serves as an early warning system, alerting users to an abnormal condition within the unit’s sealed environment.

In essence, the E20 error code is not just a random fault but a deliberate and proactive signal from the dishwasher’s monitoring system that water is present where it shouldn’t be. The design intent behind this feature is to help maintain the appliance’s integrity by minimizing the risk of serious water-related damage.

 
Internal Drainage Obstructions
 

• Accumulated food particles, soap residue, and foreign debris can lead to blockages in the drain pathway, hindering proper water egress.
• Clogs may form in the filter assembly, drain hose, or sump, reducing the efficiency of the drainage system and causing an overabundance of water to remain in the base of the appliance.
• Residue build-up over time can restrict or block the impeller of the drain pump, impeding its function even when no obvious blockage is visible externally.

 
Electrical and Sensor Anomalies
 

• Faulty wiring or loose connections associated with internal sensors may intermittently trigger error indications due to misreadings.
• Moisture accumulation or corrosion on sensor terminals can lead to erroneous signals being transmitted to the control board, falsely indicating drainage issues.
• A malfunctioning electronic control unit, which interprets various sensor data, might misdiagnose normal operations as anomalies, suggesting a need for internal inspection of connections and circuitry.

 
System Components and Installation Factors
 

• An improperly aligned or installed dishwasher may experience issues with water flow and drainage, causing inadequate removal of water during the cycle.
• Defective mechanical components, such as a worn or failing pump motor, can result in diminished performance that the error code flags.
• Deterioration of hoses and seals over time can allow for improper water routing, occasionally resulting in water pooling that triggers the error code.