mypros+
Error code reference

Thermador Range Error Code 12

Fault code indicated by first LED blinking 1 time followed by second LED blinking 2 times (specific meaning not detailed in manual beyond chart…

Thermador codesThermador range codes
Avg. service call
$285
National average. Trip fee plus diagnostic plus labor. Before parts.
MyPros+ 3-day pass
$9.95
Same diagnostic steps, on your phone. Start now.
You keep in your pocket
~$275
Even before you buy the part.
Skip the service call. Fix it yourself.
Full procedure unlocks instantly.
Get Started

What the 12 error code actually means

Your Thermador range is signaling a problem through a blinking light pattern, one blink followed by two blinks, which is how the appliance communicates this specific fault. The exact cause isn't described in simple terms by the range's indicator chart, so a technician will need to inspect the unit to pinpoint the issue. It is best to avoid using the range until the fault is diagnosed, since control board errors can sometimes indicate an underlying safety-related problem.

Diagnostic procedure

The full 12 procedure

Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.

MyPros+ · DiagnosticsStep 1 preview
1
Confirm the fault
Power cycle the unit: switch off the breaker for 60 seconds, then restore power. If the code returns, the fault is persistent and the procedure below isolates the cause.
Unlock with pass
Unlock with pass
Unlock with pass
More steps, wiring diagram references, and verified part numbers
Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.
Unlock 12 procedure $9.95

Or subscribe: $29/month for unlimited access to all codes plus Max AI diagnostics.

Most common causes of 12

Ranked by how often they cause this code
  1. 1Loose or corroded wiring connections
  2. 2Faulty main control board
  3. 3Failed or out-of-range temperature sensor
  4. 4Intermittent power supply issue
  5. 5Safety relay fault

Most DIYers save hundreds by diagnosing before ordering parts.

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass

Questions people ask about 12

What does 12 mean on a Thermador range?
Error code 12 on a Thermador range is indicated by the first LED blinking once and the second LED blinking twice in sequence. It is part of the range's built-in fault reporting system and signals that the control board has detected an abnormal condition. The specific component or circuit involved is not fully detailed in the fault chart, so hands-on diagnosis is needed to identify the root cause.
Is error code 12 on a Thermador range a safety concern?
Any control board fault code on a range warrants caution, since the board governs safety-critical functions like ignition control and temperature regulation. Until the fault is properly diagnosed, it is advisable to stop using the range. If you notice unusual smells, sparking, or the range behaving erratically alongside this code, discontinue use immediately and contact a technician.
How much does it cost to repair error code 12 on a Thermador range?
Repair costs depend heavily on what component is at fault. Basic service calls and wiring repairs typically run in the range of $100 to $250, while replacing a main control board on a Thermador range can cost between $300 and $600 or more depending on the part and labor involved. Getting a diagnostic visit from a qualified technician is the best way to get an accurate estimate for your specific situation.
Can I fix error code 12 on my Thermador range myself?
Some basic checks, such as inspecting wiring connections and ensuring the range is receiving proper voltage, can be performed by a knowledgeable DIYer. However, because the specific cause of code 12 is not fully documented, deeper diagnosis involving the control board, sensors, or relays is best handled by a qualified appliance technician. Attempting repairs without proper diagnosis risks missing the actual fault or creating additional problems.
Will resetting my Thermador range clear error code 12?
A reset, performed by cutting power to the range at the breaker for a few minutes and restoring it, may temporarily clear the blinking LED sequence. However, if the underlying fault condition still exists, the code will likely return during or after the next use. A reset is useful for ruling out a one-time power fluctuation but is not a substitute for proper diagnosis and repair.

Related Thermador range error codes

All Thermador range codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass