E45
Bosch Dishwasher
Severity: ModerateWhat Does This Error Mean?
The E45 error on a Bosch dishwasher means the NTC temperature sensor is reading a value outside its normal range. NTC stands for Negative Temperature Coefficient — it is the thermistor inside the dishwasher that monitors water temperature throughout the wash cycle. The control board uses this reading to heat water to the right temperature for cleaning and sanitizing. When the sensor reading is implausible (too high, too low, or erratic), E45 is triggered and the dishwasher stops.
Affected Models
- SHPM88Z75N
- SHPM65Z55N
- SHEM63W55N
- SHP865ZD5N
- SHDX5EM3N
- Most Bosch 300, 500, and 800 series dishwashers
Common Causes
- Failed NTC temperature sensor — resistance has drifted far out of the normal range
- Wiring connector at the NTC sensor is corroded or has come loose
- Broken wire in the NTC sensor harness — common near the sump where wires are exposed to heat
- Scale or mineral deposits coating the sensor surface, causing inaccurate readings
- Control board NTC input circuit failure — the board cannot accurately read the sensor
How to Fix It
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Turn off the dishwasher at the circuit breaker for 10 minutes, then restore power and run a short cycle. A one-time sensor glitch from a power event may clear with a full reset.
If E45 returns within the first few minutes, the fault is persistent and hands-on diagnosis is needed.
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Locate the NTC sensor. On most Bosch dishwashers, it is mounted in the sump assembly at the bottom of the tub, often clipped to the circulation pump housing or sump body. It is a small component with two wires.
You may need to remove the lower spray arm and filter assembly to clearly see the sensor.
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Inspect the sensor connector and wiring. Pull the wiring gently to check that wires are firmly attached. Look for corrosion, white mineral deposits, or heat damage on the wires and connector pins.
The sump area is constantly exposed to hot water and steam, making sensor connectors particularly prone to corrosion.
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Test the NTC sensor with a multimeter. Disconnect the sensor connector and measure resistance at room temperature — a healthy Bosch NTC sensor typically reads 4,000 to 6,000 ohms at 77°F (25°C). An open or shorted reading indicates a failed sensor.
For accurate testing, the sensor should be at a known temperature. Room temperature testing is a reliable starting point.
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Replace the NTC sensor if it fails the resistance test. Install the new sensor in the same location, reconnect the wiring, and run a full wash cycle to confirm E45 is cleared and temperatures are reaching normal levels.
Clean any mineral scale from the sump area before installing the new sensor — heavy scale buildup can insulate the new sensor and cause inaccurate readings.
When to Call a Professional
NTC sensor replacement is a moderate DIY repair if you are comfortable with basic appliance work. Sensors typically cost $10 to $30. If a new sensor does not fix E45, a technician should test the control board input circuit. Board replacement runs $150 to $350.
Frequently Asked Questions
What happens to cleaning performance if the NTC sensor fails?
Without accurate temperature feedback, the dishwasher cannot heat water to the correct temperature. You may get dishes that come out with food residue or a greasy film — signs of inadequate wash temperature. Sanitizing cycles (which require 150°F / 65°C or higher) will not function correctly either.
Can hard water cause E45?
Yes, indirectly. In hard water areas, mineral scale builds up on the NTC sensor over time. This coating insulates the sensor from the actual water temperature, causing inaccurate readings. Using a dishwasher rinse aid and descaler regularly can slow this buildup.
Is E45 the same fault as E30 on Bosch dishwashers?
No. E30 is a heating element fault — the heater itself is not working. E45 is a temperature sensor fault — the sensor is not reading correctly. Both affect the heating system but are different components. You can have E45 with a perfectly good heater, or E30 with a perfectly good sensor.