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Error code reference

Bosch Washer Error Code 43

Drum motor does not rotate

Bosch codesBosch washer codes

Drum motor does not rotate - speed sensor broken, drum blocked by laundry, motor blocked, control broken (Triac broken).

First step from the service manual

Reset error with activating test mode, check load, check speed sensor, check control, check wire harness.

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

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  • Wiring diagram references and connector pinouts from the OEM service manual
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What 43 means on a Bosch washer

Error code 43 on a Bosch washer indicates that the drum motor has failed to rotate, or the control board has lost communication with the speed sensor and cannot confirm rotation is occurring. The control board monitors drum speed through a dedicated speed sensor (also called a tachometer or hall sensor) mounted on the motor. When the sensor signal is absent or outside the expected range during a wash or spin cycle, the board logs error 43 and halts the cycle to prevent mechanical damage.

There are four primary causes the control system flags under this code: a broken or disconnected speed sensor, a drum physically blocked by laundry or a foreign object, a seized or failed drive motor, and a faulty control board with a failed Triac. The Triac is the switching component on the control board that governs motor operation. If it fails in an open or short condition, the motor will not receive the drive signal, and the drum will not turn regardless of the motor's own condition.

Diagnosis begins by activating the washer's test mode to attempt a reset and observe whether the drum will rotate under controlled conditions. From there, technicians should inspect the load for imbalance or blockage, verify speed sensor continuity and wiring, test the motor windings for resistance values within specification, and inspect the wire harness for damaged or corroded connections between the sensor, motor, and control board. If all field components test within spec, attention shifts to the control board itself.

Source: manufacturer service documentation.

Common causes of 43

  1. 01

    Overloaded or blocked drum

    Wiring / connection

    Excess laundry or a foreign object lodged between the drum and the tub can physically prevent the motor from turning. Redistribute or remove the load and check for trapped items like coins or small garments before proceeding with electrical diagnosis.

  2. 02

    Broken or faulty speed sensor

    Part replacement

    The speed sensor monitors drum rotation and sends feedback to the control board. If the sensor has failed or its wiring has broken continuity, the board receives no rotation signal and triggers error 43. Inspect the sensor and its harness connector for damage, corrosion, or open circuits.

  3. 03

    Damaged wire harness

    Wiring / connection

    Loose, pinched, or corroded wiring between the speed sensor, motor, and control board can interrupt signal transmission without any individual component being defective. Carefully trace and inspect the harness for chafing, broken terminals, or failed connector pins.

  4. 04

    Failed drive motor

    Part replacement

    A seized or burned-out drum motor will not turn regardless of control signals. Test motor winding resistance to determine if the motor is mechanically or electrically failed. A blocked or shorted motor will often show out-of-range resistance or visible heat damage.

  5. 05

    Faulty control board (failed Triac)

    Part replacement

    The Triac on the control board is responsible for switching power to the drive motor. A failed Triac prevents the motor from receiving the drive signal, causing a no-rotation condition even when the motor and sensor are intact. This is typically diagnosed after all other components have tested within specification.

See the test procedure for each cause

Frequently asked questions about 43

What does 43 mean on a Bosch washer?
Error code 43 on a Bosch washer means the drum motor is not rotating and the control board cannot confirm movement through the speed sensor. The code can be triggered by a blocked drum, a broken speed sensor, a failed drive motor, or a faulty control board Triac. The washer halts the cycle automatically to prevent mechanical damage. Diagnosis involves testing each of these components along with the wire harness connecting them.
Can I fix error code 43 on my Bosch washer myself?
Some causes of error 43 are DIY-friendly, such as removing excess laundry, clearing a blocked drum, or checking for loose wire harness connections. However, replacing the speed sensor, drive motor, or control board requires working with electrical components and a degree of disassembly experience. If you are not comfortable testing components with a multimeter or accessing internal washer parts, it is advisable to contact a qualified appliance repair technician.
Is it safe to continue using my Bosch washer when error 43 appears?
You should not attempt to run wash cycles while error 43 is active. The drum is not rotating, which means laundry will sit in water without being properly agitated or spun, potentially causing mold or garment damage. More importantly, an underlying motor or control board fault could worsen with repeated operation. Resolve the fault before resuming normal use.
How much does it cost to repair a Bosch washer error 43?
Repair costs vary significantly depending on which component has failed. Speed sensor replacements tend to be the least expensive, typically in the range of $50 to $150 including parts and labor. Drive motor replacements can range from $150 to $350 or more depending on the model. Control board replacement, which involves Triac failure, is usually the most costly repair, often falling between $200 and $450. A diagnostic service call fee will typically apply on top of parts and labor costs.
Will resetting my Bosch washer clear error code 43?
Activating the test mode to reset the error is the recommended first diagnostic step, and in some cases, particularly when the drum was temporarily blocked by laundry, the reset will allow the washer to resume normal operation. However, if an underlying component such as the speed sensor, motor, or control board is genuinely faulty, the error code will return once the washer attempts another cycle. A reset alone should be considered a diagnostic step, not a permanent fix.

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