What F45 really means

When a Bosch oven throws F45, it’s almost always the control board telling you it’s getting the wrong “door status” signal. Modern ovens won’t heat—or especially won’t run self-clean—unless they know the door is securely latched. That confirmation comes from tiny door-latch micro-switches (and, on some models, a small lock motor/actuator). If those switches don’t open and close exactly when they should, the board flags an error and you see F45.

How this shows up in real life

You might notice the oven refusing to start a bake cycle, canceling self-clean immediately, or flashing the lock icon while the door still opens freely. Sometimes the door feels like it almost latches but doesn’t quite “click,” or it latches and the error appears anyway. All of that points to the latch assembly and its switches being out of position, dirty, worn, or misread by the wiring.

Common triggers

A gentle bump to the door, a slightly bent hinge, heat-soaked plastic from frequent self-clean cycles, or even a little baked-on grease around the latch can put the switch timing out of spec. Less often, the wiring harness to the latch or the lock motor itself ages out and stops traveling the full distance, so the switches never report a true “locked” state.

Quick checks you can do safely

Unplug the oven or switch off the breaker first—no exceptions. Then open and close the door a few times and pay attention to the latch feel. You’re looking for a positive, consistent catch. If it feels gritty or sticky, clean the latch “beak” and the strike plate on the door with a soft brush and a bit of mild degreaser; residue here can keep the switch from actuating. If the door looks slightly proud on one side, the hinge may be out of alignment—closing the door gently while lifting up or supporting the weight can tell you whether alignment is part of the story.

A simple reset that sometimes helps

After cleaning, restore power and try a basic reset: keep the door closed, power the oven on, and wait 60–90 seconds so the control can re-read the latch state. If F45 clears temporarily and then returns, the switch is probably borderline—working mechanically but not electrically reliable.

When to bring out a multimeter

If you’re comfortable with basic diagnostics, disconnect power again and access the latch assembly (on many models it’s behind the front panel or just inside the top). You’ll see one or two micro-switches with two spade connectors each. Remove a connector at a time and check continuity as you manually move the latch; each switch should change cleanly from open to closed. A switch that never changes state—or flickers unpredictably—needs replacement. While you’re there, inspect the harness for heat damage or loose spades, and check that the lock motor travels its full stroke without binding.

When a professional makes sense

If the door closes perfectly and the latch is clean but F45 sticks around, you’ve likely got a failing micro-switch, a weak lock motor, or a wiring/board issue. Those parts are inexpensive individually, but accessing them can be fiddly and easy to misalign. A pro will confirm the fault quickly, replace the latch assembly or the switch, and recalibrate the door so the board reads a crisp “locked/unlocked” every time.

How to prevent F45 from coming back

Treat the door gently—don’t lean on it when open. Keep the latch area clean during routine wipe-downs. Avoid running self-clean back-to-back; extreme heat ages plastics and switch actuators faster. And if you ever feel the door losing that reassuring “click,” address it early before heat cycles make the misalignment worse.

F45 isn’t mysterious: it’s your oven saying, “I don’t believe the door is safely locked.” Most cases come down to a sticky latch, a tired micro-switch, or a weak lock motor. Start with a power-off clean and a careful door check. If the code persists, a quick continuity test or a visit from a technician will get you back to baking without warnings.