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Error code reference
Bosch Microwave Error Code E4
Thermistor short circuit detected.
SourceBosch Speed Microwave - Full Service Manual (HMC54151UC)p. 22
Diagnostic procedure
The full E4 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
1
First diagnostic step
If detected, unit reverts to plug-in mode; display shows error code for 3 seconds. Check thermistor and wiring for short circuit.
SourceBosch Speed Microwave - Full Service Manual (HMC54151UC)p. 22
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
1 manual in the MyPros+ library documents this code for Bosch microwave.
Models covered by the manuals that document this code
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