Bosch Oven Showing Error Code F45? Here’s How to Troubleshoot

If your Bosch oven is throwing an F45 error code, don’t worry, it’s a fixable issue and not as scary as it looks. We’ll walk you through what the F45 error means, the most common causes, and how you can troubleshoot and fix it yourself without needing to call in a repair service.

If you find out that you need any replacement parts for your appliance while you’re troubleshooting, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.

The information in this article may not apply to your specific appliance model. We recommend consulting your manufacturer’s documentation or contact us with any questions.

What is the F45 error code?

The F45 error code indicates a problem with the upper oven door latch in Bosch double wall ovens.

Specifically, it means the electronic control board is receiving conflicting signals that the door is both locked and unlocked at the same time. This understandably confuses the control board.

Inside your double oven, the upper and lower ovens each have their independent latch mechanisms. The latch uses a motor and switch assembly to lock the door during self-cleaning cycles and unlock when cooling completes.

Two switches provide door position status back to the control board. When the F45 code is thrown, the control sees both switches active simultaneously, meaning the door is reporting that it’s somehow both locked and unlocked at once.

Dangers of the F45 error

This contradictory status information will cause the latch to function incorrectly. It may fail to lock or unlock the door when commanded.

But the most serious side effect of an F45 error is that it will disable the self-cleaning function in that oven. The control board will not allow the high-heat self-cleaning cycle to start if it cannot properly monitor and control the door locking.

This means you’ll lose the ability to turn on the self-cleaning mode in the upper oven until the root cause of the F45 is resolved.

Troubleshooting and fixing an F45 error

To get your oven’s self-clean mode operational again, you’ll need to troubleshoot and repair the upper latch mechanism. Here is the recommended procedure:

Step 1: Inspection of latch switch wiring

Since faulty wiring is the most common cause of intermittent latch operation, the first troubleshooting step is to thoroughly inspect the switch wiring harness.

The latch assembly uses two switches mounted near the oven door lock rods to indicate the door position – one for locked and one for unlocked.

Follow the wiring harness from the switches to where it connects to the Power Board at P4.

1. Remove the harness from P4 and examine both sides of the connector. Make sure the pins are straight and the contact surfaces are clean. Bent pins or corrosion can cause resistance.
2. Use a magnifying glass to inspect each wire in the harness for damage. Look for any sections with cracked or burnt insulation that could expose copper and cause shorts.
3. Perform a “wiggle test” on each wire in the harness while watching for intermittent continuity on a multimeter. This can reveal breaks in wire strands that make faulty contact under vibration.
4. Check continuity end-to-end through each wire in the harness. Measure resistance around any splices or repairs to check for poor crimps.
5. Verify that each wire is securely fastened to the correct pin on P4 per the oven wiring diagram. Tug gently on connections to confirm good insertion tension.
6. Remove and reseat the harness into P4, then tug again to ensure a snug fit. The weight of the harness can loosen connections over time.

Take your time thoroughly examining every inch of the latch switch wiring. Intermittent shorts or opens can cause random status signals that confuse the control board.

Step 2: Careful testing of latch switch operation

Next, test the operation of the individual latch switches:

• Actuate the lock mechanism by hand while watching and listening for the audible click of each switch lever. The clicks should be crisp when opening and closing.
• Toggle the switch levers while monitoring continuity on a multimeter. Check for any flickering or questionable readings that could indicate faulty contact.
• Power up the oven and monitor the latch status on the display as you manually operate each switch. The display should immediately reflect whether the door is open or closed.
• Remove any debris and blow out the switch body with compressed air. Clean contact points with electrical contact cleaner or rubbing alcohol.
• If any anomaly is noticed, fully remove the switch from the oven for closer inspection. Look for contact wear, alignment issues, or loose/corroded terminations.

Both latch switches must provide clean, reliable signals to avoid confusing the delicate control board logic.

Step 3: Isolate short circuits in wiring

If the components and circuits check out electrically, the next step is to isolate any shorts between the locked and unlocked switch wires that could cause status conflicts.

• Disconnect the wiring harness from the Power Board again. Use a multimeter to check each pin on P4 for continuity or shorts to other pins.
• Visually inspect wires for signs of damage. Look for any points where the bare wire could be touching and creating a short between circuits. This often happens where wires are pinched or routings intersect.
• Cut back and sleeve any suspect sections of damaged wire. Do not just tape over nicks – this often fails over time.
• Power up the oven and watch for shorts as you flex and vibrate the harness by hand, especially near any repairs. Intermittent shorts often show up during the manipulation.

Be meticulous about isolating and repairing any shorts between the latch status circuits. Even the tiniest breach can lead to phantom signals and F45 faults.

Step 4: Replacement of power board

After all wiring and components measure electrically sound, latent control board failure becomes the prime suspect. Faulty processing of status circuits is a common Power Board fault indication.

Obtain an exact replacement board for your model number and carefully install it, watching for any wires caught under the board that could short.

Fully test lock and unlock cycles once installed to see if the new board resolves the F45 issue. Try initiating several self-clean modes to be sure.

If the fault persists, take a close look at the ribbon harness between boards, and the Display Board itself. But the Power Board is most frequently the culprit in confusing latch issues.

Be patient and attack the issue methodically. Keep the tips above at hand and you’ll get your double oven back to providing years of reliable service in no time.

Additional information

Thank you for reading! We hope this guide helped you get your oven working again.

If you have any other appliance repair needs or projects, don’t hesitate to explore our other troubleshooting guides and videos. 

If you need replacement parts or some extra help with ordering them, grab your model number and head over to AppliancePartsPros.com, where you can chat with a pro, read our DIY blog and more.

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