Bosch Wall Oven E312 Error Code

E312 is easy to misread as a cooking-temperature problem. A Bosch wall oven does have a cavity sensor that regulates baking, but this code concerns another part. The manufacturer’s service manual, written for its 2007 line of 300, 500 and 800 Series built-ins, defines E312 as a defective control module PCB temperature sensor. That is a small sensor on a circuit board.

The board in question

Technicians call this board the control module or the relay board. You find it at the top of the oven beneath an access panel, where it passes power on to the heating elements and other loads. For the same board running hotter than 212°F (100°C), Bosch uses E303. E312 reports that the board’s sensor itself is faulty. The board need not be hot at all.

Things to do and things that will not matter

1. Turn the oven’s breaker off for half a minute, switch it on, and see whether E312 returns. Write down when it appears.
2. Skip cooling the oven, changing the offset for temperature in the settings menu and replacing the cavity sensor. The sensor named by this code is untouched by all three.

No test for E312 appears in the manual. Because the sensor is a piece of the control module, a confirmed fault means module repair. For that job the instructions begin with reseating every connector. Once the replacement is fitted, the oven gets a reset and a test run.

Codes close to E312

• E303 covers the control module going above 212°F.
• E012 is the same kind of sensor fault, but on the user interface board.
• E310 is a data memory error on this module.

Wall oven repair, Los Angeles

When E312 will not go away after the reset, ring (310) 879-1577. Have the oven’s FD number ready; it is on the data plate below the control panel and tells when the oven was built.

Source: Bosch Service Manual, 300/500/800 Series Built-in Wall Ovens