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Error code reference

Bosch Washer Error Code F:38

Error of temperature sensor: short-circuit

Bosch codesBosch washer codes

Error of temperature sensor: short-circuit — NTC is broken.

First step from the service manual

Check NTC, check wire harness.

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

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What F:38 means on a Bosch washer

The F:38 error code on a Bosch washer indicates a fault in the water temperature sensing circuit, specifically a short-circuit condition within the NTC (Negative Temperature Coefficient) thermistor. An NTC thermistor is a resistive sensor whose resistance decreases predictably as temperature increases, allowing the control board to monitor wash water temperature in real time. When the control board detects a resistance reading that falls outside the expected range due to a short-circuit, it flags F:38 and typically halts the cycle to prevent overheating or improper wash temperatures.

A short-circuit in the NTC circuit means the sensor is either internally failed, or the wiring harness connecting it to the control board has developed a fault such as pinched wires, chafed insulation causing conductors to contact each other, or a corroded connector creating unintended continuity. Unlike an open-circuit fault, a short-circuit causes the resistance to drop abnormally low, which the control board interprets as an impossibly high temperature reading, triggering the error.

Diagnosing F:38 requires inspecting the NTC sensor and its wiring harness carefully. The NTC should be tested with a multimeter to verify its resistance at a known temperature. A shorted sensor will typically show near-zero resistance rather than the expected value for the current water or ambient temperature. The wire harness should be traced from the sensor to the control board connector, checking for visible damage, pinch points near cabinet edges, and moisture intrusion at connectors.

Source: manufacturer service documentation.

Common causes of F:38

  1. 01

    Failed NTC thermistor (internal short)

    Part replacement

    The NTC sensor itself has developed an internal short-circuit, causing its resistance to drop to near zero. Testing the sensor with a multimeter will show abnormally low or zero resistance regardless of temperature.

  2. 02

    Damaged or pinched wire harness

    Wiring / connection

    The wiring between the NTC sensor and the control board may be pinched, chafed, or abraded, causing two conductors to contact each other and create a short. Carefully trace the harness along its full routing path and inspect for visible damage.

  3. 03

    Corroded or contaminated connector

    Wiring / connection

    Moisture or detergent residue can cause corrosion at the NTC connector or the control board connector, leading to unintended electrical continuity. Inspect all connectors in the sensor circuit for discoloration, rust, or debris.

  4. 04

    Water intrusion into the sensor or connector

    Part replacement

    If water has reached the NTC sensor housing or its connector, it can create a short-circuit path between terminals. Check the sensor mounting location and surrounding area for signs of leaking or moisture accumulation.

See the test procedure for each cause

Frequently asked questions about F:38

What does F:38 mean on a Bosch washer?
F:38 on a Bosch washer indicates a short-circuit fault in the NTC temperature sensor circuit. The NTC thermistor is the component that monitors water temperature during the wash cycle, and a short-circuit causes its resistance to read abnormally low. The control board interprets this as a sensor failure and stops the cycle. The sensor itself or its wiring harness is the most likely source of the fault.
Can I fix the F:38 error myself?
Some homeowners with electrical testing experience can diagnose F:38 by inspecting the wire harness for visible damage and checking connector conditions. However, testing the NTC sensor accurately requires a multimeter and the ability to safely access internal components. If the sensor needs replacement, it is a straightforward part swap, but working inside a washer involves electrical hazards and the machine should be unplugged before any inspection.
Is it safe to keep using my Bosch washer when F:38 is displayed?
It is not recommended to continue running wash cycles while F:38 is active. The temperature sensor fault means the control board cannot accurately monitor water temperature, which could result in washing at incorrect temperatures. The washer may also refuse to complete cycles until the fault is resolved. Addressing the error promptly prevents potential issues with wash performance or further component stress.
Will resetting the washer clear the F:38 error code?
A reset may temporarily clear the error code display, but F:38 will return as soon as the control board attempts to read the NTC sensor again and detects the short-circuit condition. The underlying hardware fault in the sensor or wiring must be repaired before the error will clear permanently. Repeated resets without fixing the root cause will not resolve the problem.
How much does it cost to repair a Bosch washer F:38 error?
Repair costs for F:38 vary depending on whether the issue is a failed NTC sensor or a wiring harness problem. An NTC sensor part typically falls in a relatively modest price range, while labor costs for a technician to diagnose and replace components can add to the total. If only the harness connectors need cleaning or repair, costs may be lower. Overall repair estimates generally range from around $80 to $250 depending on parts needed and local labor rates.

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