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Error code reference

Bosch Washer Error Code Er:03

Door lock doesn't lock

Bosch codesBosch washer codes

Door lock doesn't lock — jammed lock or bad wire harness.

First step from the service manual

Check door lock mechanism and wire harness.

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

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What Er:03 means on a Bosch washer

Er:03 on a Bosch washer indicates that the door lock mechanism has failed to engage within the expected timeframe after a cycle start command is issued. The control board monitors the door lock assembly (also called the door latch or interlock) through a circuit that confirms when the lock has physically actuated and secured. When the board sends the lock signal but receives no confirmation that the lock has engaged, it triggers Er:03 and halts the cycle to prevent operation with an unsecured door.

The two primary failure points are the door lock assembly itself and the wire harness connecting it to the control board. A jammed or worn lock mechanism may fail to actuate even when it receives the correct electrical signal, which can happen due to physical obstructions, a seized actuator, or worn internal components in the latch. In some cases, the door strike on the door itself can be misaligned, preventing the lock tab from seating properly.

Wire harness issues are the second major cause. Damaged, corroded, or loose connector pins between the door lock and the control board can interrupt the signal path, causing the board to read a failed lock even if the lock mechanism itself is functional. Diagnosing this code correctly requires inspecting both the physical operation of the latch and the continuity and connection integrity of the wiring circuit.

Source: manufacturer service documentation.

Common causes of Er:03

  1. 01

    Jammed or faulty door lock assembly

    Part replacement

    The lock actuator inside the latch assembly may be seized, worn, or physically obstructed, preventing it from engaging. Try manually pressing and releasing the door lock tab to check for smooth movement. If it feels stiff or does not spring back, the assembly likely needs replacement.

  2. 02

    Damaged or disconnected wire harness

    Wiring / connection

    The wiring between the door lock and the control board can develop broken wires, corroded terminals, or loose connector pins. Inspect the harness visually for visible damage and check that all connectors are fully seated. A continuity test on the wiring can confirm whether the signal path is intact.

  3. 03

    Misaligned door strike

    Wiring / connection

    If the plastic or metal strike on the door is bent or shifted out of position, the lock tab cannot engage it properly even if the latch mechanism is working correctly. Check the alignment of the door relative to the door frame and inspect the strike for visible deformation.

  4. 04

    Worn or broken door hinge

    Part replacement

    A sagging door caused by worn hinges can misalign the latch and strike enough to prevent engagement. Check whether the door sits evenly and closes flush with the front panel. If the door droops noticeably, hinge replacement may be needed to restore proper alignment.

  5. 05

    Control board not sending lock signal

    Part replacement

    In less common cases, the control board may fail to deliver the correct voltage signal to the door lock assembly. If the lock mechanism and wiring both test as functional, the control board becomes a suspect. This should be diagnosed last after ruling out all other causes.

See the test procedure for each cause

Frequently asked questions about Er:03

What does Er:03 mean on a Bosch washer?
Er:03 means the door lock failed to engage when the washer attempted to start a cycle. The control board sends a signal to lock the door and waits for confirmation that the lock has actuated. If that confirmation does not come back, the washer halts and displays Er:03. The most common causes are a jammed lock mechanism or a wiring problem in the door lock circuit.
Can I fix Er:03 on my Bosch washer myself?
Some causes of Er:03 are DIY-friendly. Checking for obstructions around the door latch, verifying that all wire connectors are fully seated, and inspecting the door alignment for hinge issues are all tasks within reach of a careful DIYer. Replacing the door lock assembly is also straightforward on most Bosch models and requires only basic tools. Control board diagnosis and replacement are better left to a qualified technician.
Is it safe to use my washer when Er:03 is showing?
No. The washer intentionally prevents operation when Er:03 is active because the door lock must be confirmed as engaged before a wash cycle runs. Running a washer with an unsecured door creates a risk of the door opening during a cycle, which can cause water leakage and potential injury. The machine should not be used until the underlying fault is resolved.
Will resetting my Bosch washer clear the Er:03 code?
A reset may temporarily clear the code from the display, but Er:03 will return immediately when the washer attempts to lock the door again if the underlying problem has not been fixed. A reset is useful for confirming whether the fault is intermittent, such as a loose connector, but it is not a permanent solution. The door lock mechanism and wiring must be inspected and repaired to resolve the error.
How much does it cost to repair a Bosch washer showing Er:03?
Repair costs depend on what component is at fault. A replacement door lock assembly typically costs between $30 and $80 for the part alone, with professional labor adding $80 to $150 depending on your area. Wire harness repairs can be less expensive if only a connector needs reseating or a short section of wire needs repair. Control board replacement is the most expensive outcome, with parts alone ranging from $150 to $350 or more.

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