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Error code reference

Bosch Dryer Error Code 17

Filter LED flashes while filter is clean, indicating possible overheating or defective NTC R2/NTC R4.

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Filter LED flashes while filter is clean, indicating possible overheating or defective NTC R2/NTC R4.

First step from the service manual

Check for overheating (see Error 4); remove cable from power module and test NTC R2 or NTC R4, cable, and plug-and-socket connection.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What 17 means on a Bosch dryer

Error code 17 on a Bosch dryer occurs when the Filter LED flashes even though the lint filter is clean and unobstructed. This signals that the dryer's control system has detected an abnormal condition via one of two NTC (negative temperature coefficient) thermistor sensors, specifically NTC R2 or NTC R4. These sensors are resistive temperature devices mounted within the dryer's airflow or heating circuit, and they report real-time temperature data back to the power module. When a sensor fails or sends an out-of-range signal, the control logic interprets this as a potential overheating event and triggers the Filter LED as a warning.

The two most likely root causes are a genuine overheating condition or a defective NTC sensor. Overheating can result from restricted airflow, a blocked exhaust duct, or a failed heating component that causes temperatures to climb beyond normal operating thresholds. A defective NTC R2 or NTC R4 will produce incorrect resistance readings, causing the power module to flag an error even when temperatures are normal. The diagnostic procedure calls for disconnecting the cable from the power module and testing the resistance of NTC R2 or NTC R4 directly, along with inspecting the associated cable and plug-and-socket connections for continuity, corrosion, or damage.

Before isolating the NTC sensors, technicians should first rule out an actual overheating condition by reviewing the Error 4 diagnostic procedure. If overheating is confirmed, resolving airflow restrictions may clear the fault. If temperatures are within spec, resistance testing of the NTC sensors will determine whether a sensor replacement or a wiring repair is required to restore normal operation.

Source: manufacturer service documentation.

Common causes of 17

  1. 01

    Defective NTC R2 or NTC R4 temperature sensor

    Part replacement

    A failed NTC thermistor will send an incorrect resistance signal to the power module, triggering the error even when the dryer is not actually overheating. Testing the sensor resistance directly after disconnecting the cable from the power module will confirm whether the sensor is out of specification.

  2. 02

    Overheating due to restricted airflow

    Wiring / connection

    A blocked or kinked exhaust duct, a clogged lint path, or inadequate ventilation can cause internal temperatures to rise to levels that trigger the fault. Inspect the full exhaust path from the dryer to the exterior vent outlet for obstructions or damage.

  3. 03

    Damaged or corroded wiring and plug-and-socket connection

    Wiring / connection

    The cable connecting NTC R2 or NTC R4 to the power module may have corroded terminals, loose pins, or damaged insulation that cause intermittent or incorrect readings. A visual inspection and continuity test of the cable and connector will identify this issue.

  4. 04

    Faulty power module

    Part replacement

    If the NTC sensors and associated wiring both test within specification, the power module itself may be misinterpreting the sensor signals and generating a false error. This is a less common cause and should be considered only after all sensors and wiring are confirmed good.

See the test procedure for each cause

Frequently asked questions about 17

What does 17 mean on a Bosch dryer?
Error code 17 on a Bosch dryer means the Filter LED is flashing even though the lint filter is clean. This indicates that the dryer has detected a possible overheating condition or a problem with temperature sensor NTC R2 or NTC R4. The dryer's control system uses these sensors to monitor internal temperatures, and when they send an abnormal signal, the fault is triggered. A technician will need to check for overheating and test the sensors and wiring to diagnose the problem.
Can I fix Bosch dryer error code 17 myself?
Some causes of error 17 are DIY-friendly, such as clearing a blocked exhaust duct or cleaning lint buildup from the ventilation path. However, testing NTC thermistor resistance and inspecting the wiring to the power module requires disconnecting internal components and using a multimeter, which is better suited to a trained technician. If you are comfortable with basic appliance disassembly and electrical testing, the sensor and wiring checks are straightforward, but working near the power module carries electrical risk.
Is it safe to run my Bosch dryer when error 17 is showing?
It is not recommended to continue running the dryer while error 17 is active. The fault may indicate genuine overheating, which poses a fire risk if ignored. Until the root cause is identified and resolved, the dryer should remain out of service.
Will resetting my Bosch dryer clear error code 17?
A reset may temporarily clear the error display, but it will not fix the underlying problem. If the NTC sensor is defective or the wiring is damaged, the fault will return as soon as the dryer runs again. A reset is only appropriate after the actual cause has been diagnosed and repaired.
How much does it cost to repair Bosch dryer error code 17?
Repair costs depend on the root cause. Clearing an exhaust blockage yourself costs nothing beyond your time. Replacing an NTC thermistor sensor typically involves a modest parts cost, with professional labor adding to the total, making overall repair costs range from around $75 to $250 depending on the technician and your location. If the power module itself requires replacement, costs can be higher, often ranging from $200 to $400 or more including parts and labor.

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