Bosch · Oven Serious

E900 — Control Board Communication Failure

Bosch's official US oven/microwave error-code page documents only E11 (touch keys/condensation) plus generic 'E and a number' catch-alls that instruct disconnecting power and calling Bosch support. A specific 'E900' is not separately documented. The 'control board communication failure' explanation below is not confirmed on Bosch's US consumer page — verify against your model's manual.

Keep using it?
Limited use only
DIY difficulty
Moderate

How to fix it

  1. Power off at the breaker for 5 minutes and retry — clears soft comm faults.
  2. Remove the top trim/control housing and reseat the ribbon cable at BOTH ends.
  3. Inspect the cable for kinks, scorch marks, or pinches.
  4. Swap in a known-good ribbon if available.
  5. If reseating fails, replace the UI board first (cheaper, more common failure).
  6. Replace the main control if E900 returns with a new UI.

Why it happens

Typical signs: Display lit but inputs ignored · E900 at power-up · Oven won't accept bake/broil commands · Intermittent display flicker

  • Loose ribbon cable between UI and main control Heat cycling backs the connector out.
  • Damaged ribbon cable Pinched or kinked at a service step.
  • Failed user interface board Comm IC on UI no longer responds.
  • Failed main control board Master end of the bus dead.

Parts you may need

If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.

  • Bosch oven UI ribbon cable Common replacement
    Amazon →
  • Bosch user interface board Common replacement
    Amazon →
  • Bosch oven main control board Common replacement
    Amazon →

More Bosch oven codes

E005 E005 — Power Supply / Line Voltage Fault E011 E011 — Continuous Key Press Detected E0111 E0111 — Stuck Control Button E0511 E0511 — Cooling Fan Fault E0527 E0527 — Door Switch Fault E0531 E0531 — Convection Fan Fault

All Bosch codes → All oven codes →

Frequently asked questions

What does the E900 code mean on a Bosch oven?

Bosch's official US oven/microwave error-code page documents only E11 (touch keys/condensation) plus generic 'E and a number' catch-alls that instruct disconnecting power and calling Bosch support. A specific 'E900' is not separately documented. The 'control board communication failure' explanation below is not confirmed on Bosch's US consumer page — verify against your model's manual.

What causes the E900 code on a Bosch oven?

Loose ribbon cable between UI and main control: Heat cycling backs the connector out. Damaged ribbon cable: Pinched or kinked at a service step. Failed user interface board: Comm IC on UI no longer responds.

Is it safe to keep using a Bosch oven with a E900 error?

Limited use only. This is rated a serious-severity fault.

How do I fix E900 on a Bosch oven?

Power off at the breaker for 5 minutes and retry — clears soft comm faults. Remove the top trim/control housing and reseat the ribbon cable at BOTH ends. Inspect the cable for kinks, scorch marks, or pinches.

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician.