How to Fix the E302 Error Code on Bosch Ovens

Experiencing an E302 error code on your Bosch 800 Series gas slide-in range? This comprehensive guide will walk you through how to fully troubleshoot the E302 Bosch Oven error and resolve this common error code.

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 E302 error code?

The E302 error code appearing on the user interface indicates that the control module temperature sensor has detected a temperature higher than the allowable limit value on your Bosch model ranges.

Specifically, the temperature sensor on the control module has measured a temperature above the threshold of around 212°F (100°C). This triggers the error code and causes the oven’s heating elements and convection fan to shut off as a safety precaution.

The E302 error is one of the most common error codes on Bosch slide-in gas ranges. It typically appears when there is an issue with the cooling fan or a problem with the oven’s heating elements getting too hot.

There are a few potential causes of the E302 error code:

• Faulty cooling fan operation – The most likely culprit is an issue with the cooling fan. If the fan is not running at all or not spinning at the proper speed, the control module can overheat and trigger the code.
• Heating element malfunction – Faulty heating elements that are overheating or a stuck relay that is constantly sending power to the elements can also cause the E302 code.
• Ventilation obstruction – Any blockage of the ventilation paths and airflow around the oven can lead to overheating of the control module.
• Control module issue – Less commonly, there may be an issue with the temperature sensor itself on the control module board if all other components test functional.

Safety precautions

When working on any appliance, remember to keep safety first. Here are some tips to keep in mind: 

• Always power off and unplug your appliance or switch off the circuit breaker before attempting any maintenance or replacement work. This keeps you safe by preventing any risk of injury from electric shock.
• Wear insulated work gloves to protect your hands from sharp metal parts, pinching hazards and debris.
• Take your time and don’t rush while working to prevent accidents and personal injuries.
• Work in a well-lit area so you can clearly see and access the interior parts.
• Clear your workspace of clutter and other obstacles. Keep children and pets away from the work area.
• Never work on internal parts with bare wet hands. Make sure the work area is completely dry.
• Check your user manual to see if there are specific installation or safety instructions for your part or appliance. 
• Be gentle when handling or removing parts. Excessive force might damage the appliance or cause injury.
• Wear safety glasses when working with chemicals, dust or cleaning large debris to prevent injury. 
• If the appliance has recently been used, give it plenty of time for any heating parts to cool down before working on it. 
• Take pictures or make a note of wiring terminals or other connections before disconnecting to prevent any problems with reassembly.
• When working with wires, avoid touching any exposed wires or terminals. If you need to touch a wire, use a non-conductive tool or wear insulating gloves to prevent electrical shock.

Troubleshooting steps

With an understanding of what the E302 code means and what can cause it, you can now walk through this step-by-step guide to fully troubleshoot the error:

Step 1: Check the cooling fan

The cooling fan is the most likely culprit for E302 errors, so thoroughly checking its operation is the first critical troubleshooting step.

1. Start by either turning off the oven or turning off the associated circuit breaker. Then begin visually inspecting the fan. Remove the rear vented housing panel to gain access. Make sure there are no physical obstructions such as plastic bags or wires blocking the fan blades. Debris or grease buildup on the blades can also prevent proper spinning.
2. Next, listen closely to the fan as the oven heats up. You should hear the distinct hum of the convection fan motor turning on once internal temperatures rise. If you do not hear this, it’s a sign the fan is not running.
3. Go into Service Mode on the oven’s control panel and select the Cooling Fan Test. This will turn the fan on so you can verify operation. If it does not run during the test, there is a problem.
4. With the housing panel removed, check the electrical connections to the fan. Make sure the wiring harness connector is securely plugged into the fan motor. Wiggling wires or loose plugs can cause intermittent power.
5. Finally, use a multimeter to check for 120V power at the fan’s electrical connector while the oven is hot. If 120V is present but the fan still does not run, the fan motor itself will need replacement.

Step 2: Verify heating element function

Issues with the heating elements are the second most likely cause of E302 error codes. Thoroughly check them as follows:

1. Use a multimeter on the Ohms setting to check each heating element circuit for continuity. The bake and broil elements should show continuity; if not, the element needs replacement.
2. Monitor the element relay operation closely. Listen for distinct clicking sounds when the relays turn on and off to provide power to the elements during oven operation. Constant buzzing or a stuck relay indicates a problem.
3. During a bake cycle, monitor the voltage at the element connections using a multimeter. You should see 120V when the relays are closed, and 0V when they are open. Constant voltage means a stuck relay.
4. Also visually check the element terminals. Any discolored, burnt, corroded or loose connections can cause overheating and the E302 code.

Step 3: Check for ventilation obstructions

For proper airflow and cooling, the oven ventilation paths must be clear. Proper airflow ensures that the cavity temperature lowers when it needs to. Thoroughly inspect:

1. Remove all the oven racks and use a bright flashlight to look for any debris or objects blocking the oven vents along the rear wall or at the bottom. Even small items can restrict critical airflow.
2. Check that the upper and lower vent trim pieces are installed correctly. Look for any misalignments, bending or damage that could block vents. Trims must be fully intact. Make sure that the cover panel inside the oven door is secure as well to make sure there are no air leaks.
3. Use a vacuum to clean out any dust buildup around the oven ventilation openings. Any visible lint, pet hair or food debris can potentially hamper ventilation and airflow.
4. Also clean out around the cooling fan intake and exhaust areas in the rear housing panel. Dust and debris can accumulate here over time, contributing to overheating.

Step 4: Replace control module if needed

If all previous components check out fine, the E302 is likely due to a bad oven temperature sensor on the control module itself. To fully test:

1. Carefully inspect that all wiring harness connectors are plugged securely into the control module. Loose connections can cause intermittent temperature readings.
2. Check for any damaged wires or pinched harnesses in the bundle leading from the oven components to the control module. This could impact sensor signals.
3. If connections are confirmed good, replace the control module. This should resolve any internal faulty sensor issues that can cause E302 errors.
4. In rare cases, relays stuck closed on the module can lead to constant overheating. So if an E302 error persists after replacing the module, this may be the culprit. Replace the module again.

Step 5: Reassemble and retest oven

Once the source of the E302 error code is resolved, put the range fully back together and verify:

1. Re-install the back cover panel and any components that were removed during the troubleshooting process. Ensure all screws are replaced securely.
2. Restore electrical power and gas supply to the range. Reconnect anything that was disconnected for testing.
3. Clear the error code memory by accessing Service Mode on the control panel and selecting Clear Error Codes.
4. Run a full bake cycle at 350°F and broil cycle at high heat for 30+ minutes each. Monitor oven operation closely for any issues.
5. Check that the E302 error code does not reappear after thoroughly preheating the oven. The code should stay cleared after reassembly and testing.
6. If the code returns, re-check your repair work. Something may not be properly reinstalled or you need to replace an additional component. The error should stay gone with a proper fix.

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. 

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