E1 Thermador Range Error Code: A Troubleshooting Guide

If you’re seeing an E1 error code displaying on your Thermador range, it could indicate issues with electronic control board connections, power supply or the Electrically Erasable Programmable Read-Only Memory (EEPROM) chip on the board.

The EEPROM stores important calibration and configuration data like calibration values, temperature sensor data, self-clean cycle information, door lock status, and other settings that allow the control board to operate properly. Without this data, the oven’s control board can’t accurately read temperature values, initiate self-clean, lock the door, or calibrate the oven temperature. When the EEPROM chip fails, becomes corrupted, or critical data is lost, the E1 message will be displayed.

AppliancePartsPros.com is here to help you diagnose and fix the error code with this comprehensive guide.

NOTE: It’s important to check power supply voltages and control board wiring connections early on so you can avoid mistakenly replacing the control board when the error code may be caused by problems with incoming electrical power or individual wires.

What can cause the E1 error code?

The E1 fault code indicates the control board is no longer able to access vital oven configuration and calibration data from the onboard EEPROM chip. Common causes that may lead to the error include:

• Power surges or electrical spikes
• Poor control board connections resulting in data corruption
• Aged EEPROM chip reaching the end of its service life
• Defective control board due to overheating or electrical damage

READ MORE: How to Protect Your Appliances in a Power Outage

Steps for troubleshooting the code

1. Check control board connections

When you first encounter an E1 error, you should thoroughly check all connections to the electronic control board. Loose wiring or intermittent connections can allow electrical noise or power spikes to reach the control board and corrupt the EEPROM chip.

How to inspect control board connections in a Thermador range:

1. Turn off the power to the oven at the main breaker panel or unplug the range if it can be pulled out from the wall.
2. Locate the electronic control board housing in the rear of the oven compartment. It is often contained in a metal box with a removable cover.
3. Remove the cover plate or access panel to expose the control board and wiring.
4. Check that all wire connectors are fully inserted into their terminals on the control board. Carefully look for any wires that may have come loose or partly pulled out of their connectors.
5. Push any partially removed wires back into place until you feel and hear a solid snap or click.
6. Check the terminal screws on the connectors and tighten them if any are loose. Do not overtighten which can damage the screw terminals.
7. Carefully inspect the wiring for signs of damaged or deteriorated insulation and exposed copper. Any compromised wires should be replaced.
8. Check that the ground connection is sound and secured in place on the chassis ground point.
9. Examine the entire control board for any signs of physical damage, overheating, or burnt spots, which can contribute to E1 errors.
10. Reinstall the control board cover and mounting screws. Double-check that all wiring is cleanly routed before replacing covers.
11. Restore power and test the oven’s functionality.

2. Verify proper power supply voltages

If the E1 error persists after verifying control board connections, you’ll want to make sure the proper power supply voltages are reaching the board.

An incorrect power supply can damage electronic components over time or cause them to behave erratically and corrupt the EEPROM data, leading to the E1 error display.

READ MORE: How To Use A Multimeter To Check Appliance Parts

How to check power supply voltages:

1. Disconnect power to the range by turning off the circuit breaker or unplugging the unit.
2. Access the control board connections again as outlined in the previous section.
3. Set your multimeter to AC voltage mode rather than DC or continuity.
4. Place the black multimeter probe on a clean spot on the oven chassis or ground connection. This provides a ground reference.
5. Touch the red multimeter probe to the incoming L1 connection on the control board. You should measure 120 VAC compared to the ground.
6. Move the red probe to the neutral terminal. It should also read around 120 VAC compared to ground.
7. Finally, check between the L1 and L2 terminals. This should measure 240 VAC.
8. All supply voltages should be steady within a range of 108 VAC to 132 VAC and free of fluctuations.
9. If voltages are outside of the expected range, a qualified electrician will need to diagnose and repair the power supply wiring and breaker/fuse panel.
10. Restore the electronic control board access panel once the voltages are confirmed to be correct.

3. Replace a faulty control board

If all electrical connections are tight and supply voltages are within specification, the E1 error likely indicates the EEPROM chip has failed. This memory chip isn’t sold separately, so the entire control board assembly will need to be swapped out.

You can order a new Thermador main control board and cover by visiting AppliancePartsPros.com and entering your range’s model number.

NOTE: Take extreme care when handling and installing the replacement control board to avoid bending pins or damaging any components on the board.

How to replace the electronic control board:

1. Turn off power to the range at the main breaker panel or unplug the unit.
2. Remove the mounting screws from the old control board cover and carefully slide the board out from the mounts to access the connections.
3. Take note of and label all wire connectors for future reference.
4. Disconnect all wire connectors from the terminals on the board.
5. Install the replacement board, taking care to match up each wire with the corresponding connection terminal.
6. Make sure all wires are fully inserted and secure on their terminals.
7. Mount the new control board securely and reinstall the outer cover.
8. Restore electrical power. You’ll most likely need to recalibrate the oven after the new board is installed.
9. Clear any residual error codes and test oven functionality. E1 should now be resolved.

4. Recalibrate the oven sensor

After installing a new control board, the oven temperature sensor needs to be recalibrated to program the correct resistance range into the new board to maintain accurate cooking temperatures.

Follow this recalibration sequence to pair the new board with the specific temperature sensor in your oven:

1. Initiate service mode by pressing Bake, Broil, and Clean simultaneously and holding for 3 seconds.
2. Press the Bake button once to display the current temperature sensor offset value.
3. Use the Bake and Broil buttons to adjust the offset number up or down in increments of 5°F or 3°C.
4. Adjust the offset to match the calibration number printed on the sticker at the back of the oven or inside the oven door.
5. Press the Clean button once when the displayed offset matches the calibration sticker. This will exit service mode.

What to do about persistent E1 errors

If an E1 error reappears after replacing the electronic control board and sensor calibration, there still may be an issue with incoming electrical power, internal wiring, or other oven components causing EEPROM corruption. Unusual cases may require electrical repairs or extensive oven component testing to identify the root cause.

How to continue troubleshooting:

• Consult an electrician to thoroughly evaluate the power supply wiring, circuit breaker, and fuse box for faulty connections, old breakers, insufficient voltage or amperage, or wiring issues.
• Check for any damaged internal oven wiring such as wire insulation breaking down or shorting against the chassis.
• Inspect oven components like the temperature sensor, door switches, and heating elements for damage which can feed abnormal voltages back to the board.
• Review wiring diagrams to make sure all oven components are properly connected to the control board in the correct sequence.

More information

We hope that by following this comprehensive guide you’re able to resolve most occurrences of this error code.

If you need some extra assistance or replacement parts for your Thermador range, visit us at AppliancePartsPros.com or call 1-877-477-7278. On our website, you can search for parts with your model and serial numbers, chat with a pro, check out our DIY blog, and more.

Make sure to follow us on Facebook and Twitter for regular updates and subscribe to our YouTube channel, where you’ll find thousands of video tutorials.