Error code reference

Bosch Microwave Error Code F-4

Humidity sensor self-heating time exceeds 64 seconds or zero balancing voltage does not rise to 2.5 volts.

SourceBosch Microwave Oven - Full Service Manual (HMB402/405/406)p. 5-10

Diagnostic procedure

The full F-4 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

First diagnostic step

Only CLEAR key is permitted to enter; check sensor cooking conditions (oven plugged in at least 5 minutes, room temp below 95°F, ensure cooking container exterior and oven interior are dry).

SourceBosch Microwave Oven - Full Service Manual (HMB402/405/406)p. 5-10

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More steps, wiring diagram references, and verified part numbers

Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.

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Where this code is documented

2 manuals in the MyPros+ library document this code for Bosch microwave.

Models covered by the manuals that document this code

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The full F-4 procedure

Where this code is documented

Models covered by the manuals that document this code

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