Bosch oven shows E016 and shuts down during or shortly after preheat

Safety first: Disconnect power at the breaker before accessing internal components.

• Check for fan operation: Turn power back on and start a bake cycle. Listen for the top cooling fan. If it does not run or is very noisy, cancel the cycle and turn power off.
• Access fan: Remove the oven from the cabinet enough to remove the top cover. Locate the cooling fan assembly near the top rear.
• Inspect blades and ducts: Check for insulation, debris, or grease buildup blocking the fan or air channels. Clean carefully.
• Test fan motor: With power off, disconnect the fan and test for continuity. An open motor indicates it must be replaced. Also check for free rotation by spinning the blades by hand.
• Check wiring and board: Inspect the wiring harness from the main control board to the fan for burns or loose connectors. If the fan tests good but never receives power, the fan driver (triac/relay) on the main board may be faulty and the board will need replacement.