Temperature sensor
Common error-code part. Confirm resistance and connector style.
E01 on a Bosch residential dishwasher (displayed as E:01) means the heating circuit has a fault. The dishwasher runs through its cycle but water doesn’t heat — dishes come out wet, cloudy, or cold to the touch after a wash cycle.
What This Error Means
E01 indicates a problem in the heating circuit. This could be the heating element itself, the thermal fuse protecting it, the NTC temperature sensor that monitors water temperature, or a relay on the control board that switches power to the element.
E01 means the circuit has a problem detected — E09 means the element itself is definitively confirmed failed. If you see E01, diagnosis is needed to confirm which component is bad.
Common Causes
- Blown thermal fuse — The first and cheapest thing to check. The thermal fuse protects the element from overheating. Once blown, it doesn’t reset.
- Failed heating element — The element has burned out (open circuit). Very common on machines 5+ years old.
- Failed NTC temperature sensor — The sensor that tells the board the water temperature has failed.
- Failed control board relay — The relay that switches power to the element has burned out on the board.
Step-by-Step Diagnosis
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Run a confirm test. Start a normal wash cycle and 15 minutes in, open the door briefly (carefully — there may be hot water spray) and touch the water at the bottom of the tub. If it’s cold or lukewarm after 15 minutes, the heating circuit is definitely not working.
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Access the bottom of the machine. Disconnect power. Pull the dishwasher out and lay it on its back to access the bottom components, or on its side. The heating element, thermal fuse, and NTC sensor are all accessible from beneath.
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Test the thermal fuse first. It’s a small oval component near the element connections. Test continuity — a good fuse reads near-zero ohms. An open circuit (infinite) means it’s blown. Replace it.
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Test the heating element. The element wraps around the inside bottom of the tub and has two connection terminals accessible from below. Test continuity between the two terminals. No continuity means the element is open — replace it.
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Test the NTC sensor. The NTC sensor reads approximately 10,000–50,000 ohms at room temperature. Test with a multimeter — resistance should change as temperature changes. Open circuit or fixed reading = failed sensor.
Parts You May Need
- Bosch dishwasher heating element (search your model number)
- Bosch dishwasher thermal fuse
- Bosch dishwasher NTC temperature sensor
- Dishwasher descaler cleaner
When to Call a Technician
Note: Bosch Series 800 models use a flow-through heater (Durchlauferhitzer) rather than a traditional tub element. This is a different part entirely and more expensive to replace. If your model has a flow-through heater and E01 appears, a technician diagnosis is recommended before ordering parts to confirm whether the heater or an associated component has failed.