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Error code reference

Bosch Range Error Code F43

Motorized latch will not unlock when latch should be unlocked; all heating functions should be off.

Bosch codesBosch range codes

Motorized latch will not unlock when latch should be unlocked; all heating functions should be off.

First step from the service manual

Check if motor rotated and feedback switch changed state; check switch contacts A and B.

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

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What F43 means on a Bosch range

The F43 error code on a Bosch range indicates that the motorized door latch mechanism has failed to unlock after the self-clean cycle or another condition requiring the door to be released. The oven control expects the latch motor to drive the latch bolt to the unlocked position and receive confirmation from a feedback switch before the door can be opened. When the control commands the motor to unlock but does not detect the correct switch state change within the expected timeframe, it sets F43 and disables all heating functions as a safety precaution.

The core of the diagnostic process involves two checks: whether the latch motor actually rotated, and whether the feedback switch changed state in response to that rotation. The feedback switch has two contacts, labeled A and B, that signal the latch position to the control board. If the motor runs but the switch does not respond, the switch itself may be faulty or out of alignment. If the motor does not rotate at all, the fault may lie with the motor winding, wiring harness, or the control board output that drives the motor.

Common root causes include a seized or obstructed latch mechanism that prevents physical movement even when the motor energizes, a failed feedback switch with burned or open contacts at positions A or B, a motor winding that has failed open or has poor electrical connections, and wiring faults between the control board and the latch assembly. Because the oven door remains locked while F43 is active and all heating is shut down, this error should be addressed promptly to restore normal operation.

Source: manufacturer service documentation.

Common causes of F43

  1. 01

    Seized or jammed latch mechanism

    Wiring / connection

    Food debris, grease buildup, or physical deformation can prevent the latch bolt from moving freely even when the motor energizes. Inspect the latch assembly for obstructions or bent components that block travel.

  2. 02

    Failed or misaligned feedback switch

    Part replacement

    The feedback switch at contacts A and B signals the control board when the latch has reached the unlocked position. If the switch contacts are burned, open, or the switch has shifted out of alignment, the control never receives confirmation of unlocking.

  3. 03

    Latch motor failure

    Part replacement

    The latch motor winding can fail open or develop a poor connection, preventing rotation entirely. Checking for proper voltage at the motor terminals while the control commands unlocking will help confirm whether the motor or the control is at fault.

  4. 04

    Wiring harness fault between control board and latch assembly

    Wiring / connection

    A broken wire, loose connector, or corroded terminal in the harness running to the latch motor or feedback switch can interrupt both the drive signal and the position feedback. Inspect connectors and continuity along the latch circuit.

  5. 05

    Control board output failure

    Part replacement

    If the motor receives no voltage when the control attempts to unlock the latch, the relay or driver circuit on the control board responsible for energizing the latch motor may have failed. This is typically diagnosed after ruling out the motor, switch, and wiring.

See the test procedure for each cause

Frequently asked questions about F43

What does F43 mean on a Bosch range?
F43 means the motorized door latch failed to move to the unlocked position when the control commanded it to do so. The control board monitors a feedback switch with contacts A and B to confirm latch movement, and when that confirmation is not received, F43 is set. As a safety measure, the oven shuts off all heating functions when this code is active. The door will typically remain locked until the underlying fault is resolved.
Can I reset F43 on my Bosch range to clear it?
Cycling power to the oven may temporarily clear the error code display, but if the latch mechanism, feedback switch, motor, or wiring fault is still present, F43 will return as soon as the control attempts to operate the latch again. A reset is not a repair. The latch system needs to be inspected and the underlying cause corrected before the error will stay clear.
Is it safe to use my Bosch oven when F43 is showing?
When F43 is active, Bosch disables all heating functions automatically, so the oven cannot heat even if you attempt to start a cook cycle. The door will also remain locked. This means the oven is not usable for cooking until the fault is repaired, but there is no immediate safety hazard from the error itself since heating is already disabled.
How do I fix F43 on a Bosch range?
Start by checking whether the latch motor rotated and whether the feedback switch contacts A and B changed state during the unlock command. If the motor did not rotate, check for voltage at the motor and inspect the wiring harness for breaks or loose connectors. If the motor ran but the switch did not respond, the feedback switch likely needs replacement or realignment. A seized latch mechanism should be inspected for debris or damage before replacing electrical components.
How much does it cost to repair a Bosch range F43 error?
Repair costs vary depending on which component has failed. A replacement latch feedback switch typically runs in the range of $20 to $60 for the part alone. A latch motor assembly can cost between $50 and $150 in parts. If the control board is the root cause, parts alone can range from $150 to $400 or more. Adding professional labor, total repair costs commonly fall between $150 and $500 depending on the diagnosis and your location.

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