Bosch Dishwasher Error Code Test (NTC)

The Test (NTC) error means the dishwasher's temperature sensor (the NTC thermistor) has been detected as either short-circuited or open-circuited. This sensor is responsible for monitoring wash water temperature so the control board can regulate the heating element. The fault can originate from the sensor itself or from the wiring harness that connects it to the control board. Diagnosis involves measuring the sensor's resistance directly at its terminals.

It is not recommended to continue running the dishwasher with this error active. Without a functioning temperature sensor, the control board cannot accurately regulate water heating, which could result in overheating, inadequate sanitization, or the machine stopping unexpectedly mid-cycle. Addressing the fault before continued use is the safer approach.

A reset may temporarily clear the error code from the display, but the fault will return as soon as the control board runs its diagnostics and detects the same out-of-range signal from the NTC circuit. Resetting does not address the underlying hardware problem. The sensor or wiring must be inspected and repaired to permanently resolve the error.

Yes, this repair is within reach for a technically inclined DIYer. Start by disconnecting the NTC connector and using a multimeter to check resistance at the sensor terminals. A reading outside the 5.4 to 6.5 kilohm range at 20 degrees C confirms the sensor is faulty and needs replacement. If the sensor reads correctly, inspect the wire harness for damage or corrosion before concluding the control board is the issue.

If only the NTC thermistor needs replacement, parts typically cost between $15 and $50 depending on the specific model. If a professional technician performs the repair, total costs including labor generally range from $80 to $200. A faulty wire harness adds some labor time but is usually less expensive than a control board replacement, which can range from $150 to $400 or more.