Control Module Failed Its Program Memory Check: Bosch Oven E309

What E309 means

At each start-up the oven looks over the program stored on its control module before it allows any heat. E309 means that look turned up a problem, and the oven keeps every heating element off as a result. It is the sibling of E009, where the same failure is found on the user interface board. If the next start-up check passes, the message withdraws itself.

Common causes of E309

Program memory on the control module corrupted
A power interruption while memory was being written
Control module reaching the end of its life

✓ One safe check you can try

1. Switch the oven's breaker off, give it two minutes, then switch it back on so the start-up check runs again. 2. A single clean restart after a power event is not unusual. 3. A code that returns straight away tells you the check genuinely failed, so stop there and call us.

! Why to stop there

The control module carries mains voltage and sits deep in the oven.
Which board holds the damaged memory matters, since replacing the wrong one gets you nowhere.
Pressing restart again and again does not repair corrupted memory.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

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Other Oven codes

E223Lower Probe Reads Colder Than Allowed (Bosch Oven E223) E226Bosch Oven E226 After the Lower Door Latch Signal Is Lost E215Lower Cavity Overheated and Locked Itself: Bosch Oven E215 E216Lower Cavity Meat Probe Socket Problem on a Bosch Oven, E216 E222Bosch Oven E222 Where the Lower Probe Reads Hotter Than Allowed E310Bosch Oven E310 Signals a Settings Memory Failure on the Control Module E312The Control Board's Own Heat Sensor Died (Bosch Oven E312) E314Bosch Oven E314 When the Cancel or Off Key Reads Stuck

E309E309 questions

What is the difference between E009 and E309?

Both mean the memory check failed, but E009 points at the user interface board and E309 at the control module. The repair is to replace whichever board holds the damaged memory.

Can an outage cause this?

Yes. An interruption mid-write can leave memory damaged. If the code appeared after an outage, a restart may clear it; if it persists, the board needs attention.

What does the repair cost?

Control modules are one of the larger oven parts, so we confirm the diagnosis first and quote in writing before ordering. Our work carries a 30-day workmanship warranty.