mypros+
Error code reference

Bosch Dryer Error Code E:28

NTC error

Bosch codesBosch dryer codes

NTC error — break or short-circuit of NTC or cables.

First step from the service manual

Check cables and NTC.

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

MyPros+ Max

Get the full diagnostic procedure for E:28.

  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
Get the full procedure

$29/month · Cancel anytime · Or $9.95 3-day pass

What E:28 means on a Bosch dryer

The E:28 error code on a Bosch dryer indicates a fault in the NTC (Negative Temperature Coefficient) thermistor circuit. The NTC is a temperature-sensing resistor whose resistance changes predictably as temperature rises or falls. The dryer's control board continuously monitors the NTC signal to regulate heat and protect internal components from overheating. When the board detects a resistance reading that falls outside the expected range, it logs E:28 and may halt the drying cycle to prevent damage.

This fault is triggered by one of two electrical conditions: an open circuit (break) or a short circuit within the NTC sensor itself or its connecting wiring harness. A break in the circuit causes the resistance to read as infinitely high, while a short causes it to drop to near zero. Both conditions produce temperature readings that are clearly invalid, prompting the control board to flag the error. The wiring harness connecting the NTC to the control board is a common failure point due to heat exposure, vibration, and repeated flexing over time.

Diagnosis begins with a visual inspection of the cables running to the NTC, checking for pinched, burned, or disconnected wires. If the wiring looks intact, the NTC itself should be tested with a multimeter. A functioning NTC will show a measurable resistance that changes when exposed to heat from your hand or a heat gun. A reading of zero ohms or infinite resistance confirms sensor failure. The NTC is typically located in the airflow path near the drum outlet or heater assembly.

Source: manufacturer service documentation.

Common causes of E:28

  1. 01

    Damaged or disconnected wiring harness

    Wiring / connection

    The cables connecting the NTC to the control board can become pinched, burned, or disconnected over time due to heat and vibration. Visually inspect the full length of the harness for fraying, melting, or loose connectors.

  2. 02

    Failed NTC thermistor

    Part replacement

    The NTC sensor itself can fail internally, producing either an open circuit (infinite resistance) or a dead short (near-zero resistance). Testing with a multimeter will confirm whether the sensor's resistance changes appropriately with temperature.

  3. 03

    Corroded or loose connector terminals

    Wiring / connection

    Moisture and heat can cause the connector pins at the NTC or control board end to corrode, increasing resistance or breaking continuity entirely. Check both connectors for corrosion, discoloration, or loose-fitting pins.

  4. 04

    Short circuit caused by chafed wiring

    Part replacement

    If wiring insulation has worn away where cables contact the drum, cabinet frame, or other sharp edges, the bare conductors can short against each other or against the chassis. Trace the harness carefully and look for worn spots.

  5. 05

    Control board fault

    Part replacement

    In rare cases, the control board's NTC input circuit can fail, causing it to misread or not read the sensor signal at all. This should only be suspected after the NTC and all associated wiring have been confirmed good.

See the test procedure for each cause

Frequently asked questions about E:28

What does E:28 mean on a Bosch dryer?
E:28 on a Bosch dryer indicates an NTC thermistor error, specifically a break or short circuit in the temperature sensor or its wiring. The NTC is a resistor that the control board uses to monitor drum or exhaust temperature. When the board detects an invalid resistance reading, it triggers E:28 and may stop the cycle. The fault points to the sensor itself, the connecting cables, or the terminal connectors.
Can I fix the E:28 error myself?
A knowledgeable DIYer can often resolve E:28 by inspecting and reseating the wiring harness connectors or replacing the NTC thermistor, which is a relatively straightforward repair. You will need a multimeter to test the sensor and cables. If the wiring is damaged or the NTC reads open or shorted, replacing the faulty component should clear the error. If the fault persists after replacing the sensor and checking all wiring, the control board may need professional evaluation.
Is it safe to keep using my dryer when E:28 is showing?
It is not recommended to continue operating the dryer while E:28 is active. The NTC is a key safety component that tells the dryer when temperatures are reaching unsafe levels. Without reliable temperature feedback, the dryer cannot regulate heat properly, which creates a potential overheating or fire risk. Stop using the dryer until the fault is diagnosed and corrected.
How much does it cost to repair a Bosch dryer E:28 error?
If the repair requires only a new NTC thermistor, the part itself typically costs in the range of $15 to $50 depending on the specific model. If a technician is needed, total repair costs including labor generally fall in the range of $80 to $200. Wiring harness repairs or connector replacement are usually on the lower end of that range, while control board replacement would be significantly more expensive.
Will resetting the dryer clear the E:28 error code?
A power reset, such as unplugging the dryer for a few minutes and restarting it, may temporarily clear the E:28 display, but the error will return if the underlying fault is still present. The code is generated because the control board is detecting a real electrical problem with the NTC circuit. A reset does not repair a broken wire, corroded connector, or failed sensor. Proper diagnosis and repair of the root cause are required to permanently resolve the fault.

Related Bosch dryer codes

All Bosch dryer codes
View all 94 Bosch dryer codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass