Bosch Washer Error Code Er:05

Er:05 means the washer's control board has detected an open circuit in the NTC thermistor circuit, the component that monitors water temperature. This can be caused by a failed thermistor, a broken wire harness, or corroded connectors. The machine flags this fault because it cannot safely regulate the heating cycle without a valid temperature reading. Diagnosis starts with running test P16 and then checking the NTC and its wiring.

Running the washer with an active Er:05 fault is not recommended. Without a working temperature sensor, the control board cannot properly regulate water heating, which could result in overheating or an incomplete cycle. It is best to resolve the fault before continuing regular use.

A reset may temporarily clear the error code from the display, but it will return as soon as the control board checks the NTC circuit again during the next cycle. Because Er:05 reflects an actual electrical fault rather than a one-time glitch, a reset alone will not fix the underlying problem. The NTC sensor and wire harness must be inspected and repaired or replaced to permanently resolve the code.

A knowledgeable DIYer can diagnose and fix this fault in many cases. The process involves running test P16, then using a multimeter to check NTC resistance and test harness continuity. If the thermistor is confirmed faulty, replacing it is a straightforward repair. If the harness is damaged, repair or replacement requires more skill and care working around the machine's internal components.

Repair costs depend on whether the fault is in the NTC sensor, the wire harness, or the control board. An NTC thermistor replacement is typically the least expensive path, with parts generally ranging from $15 to $50. If a harness repair or control board replacement is needed, total repair costs including labor can range from $100 to $350 or more depending on your location and the specific parts required.