Bosch Washing Machine Error Codes: The Master Technician’s Guide

As a master appliance repair technician, I have spent years diagnosing, disassembling, and repairing Bosch and BSH Group laundry appliances. When a Bosch washing machine suddenly stops and displays an error code, many homeowners assume the worst. For an experienced technician, however, that code is the first step toward identifying the root cause of the failure.

This guide provides a professional breakdown of the most common Bosch washing machine error codes, their causes, and the recommended diagnostic procedures.

Water, Drainage & Door Lock Fault Codes

E16 / F16 – Door Lock Error

The control board detects that the door is open or the door lock failed to engage after a cycle has started.

Common Triggers:

• Faulty door lock assembly
• Misaligned door latch
• Damaged wiring between lock and control board
• Defective control module

Recommended Diagnosis:

• Verify proper door closure.
• Inspect the latch and strike for damage.
• Test the door lock assembly for continuity.
• Check wiring connections to the lock mechanism.

E17 / F17 – Water Inlet Time Exceeded

The washer failed to reach the required water level within the programmed time.

Common Triggers:

• Restricted water supply
• Clogged inlet screens
• Faulty water inlet valve
• Low household water pressure

Recommended Diagnosis:

• Verify water supply valves are fully open.
• Inspect inlet hoses for kinks.
• Clean inlet valve filter screens.
• Test the water inlet valve electrically.

E18 / F18 – Drain Time Exceeded

The machine could not drain water within the allowed time.

Common Triggers:

• Blocked drain pump filter
• Obstructed drain hose
• Failed drain pump
• Foreign objects in the pump impeller

Recommended Diagnosis:

• Clean the pump filter.
• Inspect the impeller for obstructions.
• Check drain hose routing and blockages.
• Test drain pump operation and resistance.

E23 / F23 – AquaStop Leak Protection Activated

Water has accumulated in the appliance base, activating the leak detection float switch.

Common Triggers:

• Internal hose leak
• Damaged tub or sump
• Leaking dispenser drawer
• Loose hose connections

Recommended Diagnosis:

• Remove the lower access panel.
• Inspect the base pan for standing water.
• Locate and repair the source of the leak.
• Reset the AquaStop system after repairs.

Heating System Fault Codes

E19 / F19 – Heating Time Exceeded

The water failed to reach the target temperature within the expected timeframe.

Common Triggers:

• Failed heating element
• Excessive scale buildup
• Faulty NTC temperature sensor
• Wiring faults

Recommended Diagnosis:

• Measure heater resistance.
• Check for earth leakage.
• Test the NTC sensor values.
• Inspect wiring between heater and control board.

E20 / F20 – Unexpected Heating Detected

The heating element is energized when it should be inactive.

Common Triggers:

• Stuck heater relay
• Shorted control board component
• Wiring fault

Recommended Diagnosis:

• Test heater relay operation.
• Inspect the control board for damaged components.
• Verify heater circuit integrity.

Motor & Drive System Fault Codes

E21 / F21 – Motor Drive Fault

The control module cannot properly operate or monitor the drum motor.

Common Triggers:

• Motor failure
• Worn carbon brushes (older models)
• Damaged motor wiring
• Faulty motor control circuitry

Recommended Diagnosis:

• Inspect motor brushes if equipped.
• Measure motor winding resistance.
• Check motor harness connections.
• Verify tachometer feedback signals.

E32 / F32 – Unbalanced Load Detected

The control system detected excessive vibration during spin acceleration.

Common Triggers:

• Uneven laundry distribution
• Worn shock absorbers
• Suspension component wear
• Faulty vibration sensor

Recommended Diagnosis:

• Redistribute the laundry load.
• Test suspension and dampers.
• Check cabinet stability.
• Inspect vibration monitoring components.

E60 / E602A – Inverter Communication Error

Communication between the motor inverter and main control board has been interrupted.

Common Triggers:

• Loose wiring connections
• Inverter module failure
• Control board fault
• Damaged harness

Recommended Diagnosis:

• Inspect inverter wiring.
• Check communication circuits.
• Verify inverter power supply.
• Test inverter module operation.

Water Level & Sensor Fault Codes

E25 / F25 – AquaSensor Fault

The optical turbidity sensor is providing invalid or missing readings.

Recommended Diagnosis:

• Clean the sensor lens.
• Check wiring connections.
• Replace the sensor if readings remain unstable.

E26 / F26 – Pressure Sensor Fault

The analog pressure sensor signal is outside acceptable limits.

Recommended Diagnosis:

• Inspect wiring and connectors.
• Check the pressure chamber for blockage.
• Test sensor voltage output.
• Replace the pressure sensor if necessary.

E27 / F27 – Pressure Sensor Calibration Error

The control board receives an implausible water level reference during initialization.

Recommended Diagnosis:

• Inspect the pressure hose for restrictions.
• Clean pressure chamber.
• Verify sensor calibration values.
• Replace the sensor if required.

E28 / F28 – Flow Sensor Error

The flow meter and pressure system report conflicting water-fill information.

Recommended Diagnosis:

• Inspect the flow meter assembly.
• Check the flow sensor impeller.
• Verify wiring integrity.
• Test pressure sensing components.

Temperature Sensor (NTC) Fault Codes

E29 / F29 – Water Inlet Temperature Sensor Error

The inlet NTC sensor is open, shorted, or providing invalid data.

Recommended Diagnosis:

• Measure NTC resistance.
• Compare readings against Bosch specifications.
• Inspect wiring harnesses.

E30 / F30 – Main Heater NTC Error

The primary tub temperature sensor has failed.

Recommended Diagnosis:

• Measure sensor resistance.
• Check connector integrity.
• Replace the sensor if values are outside specification.

E31 / F31 – Dryer NTC Error (Washer-Dryer Models)

The drying system temperature sensor is not reporting correctly.

Recommended Diagnosis:

• Clean lint accumulation around the sensor.
• Inspect wiring.
• Test resistance values.

Control Board & Communication Fault Codes

E61 / F61 – Incorrect Variant Coding

The appliance configuration stored in memory does not match the machine’s hardware profile.

Recommended Diagnosis:

• Enter service mode.
• Verify model coding.
• Perform variant programming if required.

E67 / F67 – Variant Configuration Error

Communication mismatch between the user interface and the main control module.

Recommended Diagnosis:

• Reprogram firmware.
• Verify software compatibility.
• Replace incorrectly configured modules.

E90 / E9010 – Communication Timeout

Data communication between electronic modules has been interrupted.

Common Triggers:

• Corroded connectors
• Harness damage
• Control board failure
• Low-voltage communication faults

Recommended Diagnosis:

• Inspect communication harnesses.
• Check connector pins.
• Verify module voltage supplies.
• Test network continuity.

i-DOS Automatic Dosing System Fault Codes

E1000 – Dosing Unit Control Error

The i-DOS dosing control module has detected an internal fault.

Recommended Diagnosis:

• Verify power supply to the dosing unit.
• Inspect module connections.
• Test the dosing assembly.

E1010 – i-DOS Communication Failure

Communication between the main control board and the automatic detergent dosing system has been lost.

Recommended Diagnosis:

• Remove and inspect the detergent drawer.
• Clean electrical contact points.
• Check harness connections.
• Replace the i-DOS module if communication cannot be restored.

Final Thoughts

Bosch error codes are not simply warnings—they are diagnostic tools designed to help pinpoint system failures quickly and accurately. While some issues, such as blocked filters or unbalanced loads, can be resolved by homeowners, communication faults, inverter errors, and control board failures typically require advanced testing procedures and professional diagnostic equipment.