Customer Questions and Answers for Wall Oven Control Board by Bosch

If the lower oven door on your Bosch HBL5650UC/06 locked itself while the oven was not in use, it is usually caused by one of these issues:

Control board glitch (most common) – The control may have mistakenly energized the door lock motor.
Door lock assembly or lock switch failure – The lock motor or position switches may be stuck, making the control think the oven is in a self-clean cycle.
Faulty electronic control board – If the lock continues to engage by itself, the control board may be sending power to the lock motor when it shouldn't.

Here are a few things I'd recommend trying:

Perform a hard reset. Turn the oven off at the circuit breaker for 5–10 minutes, then restore power and see if the lock retracts.
Check the display. Does it say "LOCKED", "SELF CLEAN", or show any error codes? That can help narrow down the cause.
Try starting and then canceling a self-clean cycle. Sometimes the control will drive the lock motor through a full cycle and release it when you press Cancel.

If the door remains locked after the reset, the next step is to determine whether the control board is continuously sending voltage to the door lock motor or if the door lock assembly is mechanically stuck. That test requires working with live voltage, so use appropriate caution.

Live Power Warning: Extreme care should always be taken to protect against electric shock, which could potentially result in serious injury. Please do not test live voltage if you are uncomfortable using a multimeter around live voltage. If you'd like to know more about how to use a multimeter, we've put together a comprehensive tutorial for you, so check out the link in the description.

A couple of questions that will help pinpoint the problem:

Is the upper oven operating normally, or is it affected too?
Is the lower oven display showing any error codes or messages?
When you try to unlock it, do you hear the door lock motor running or clicking, or is it completely silent?