Bosch Mini Split E3 Error Code

What E3 means

E3 means an indoor fan speed error on Bosch Climate 5000 systems - the indoor fan did not run at the speed the control expected, so the system stops to protect the coil and compressor. Clean the filter and clear anything blocking the louvre or blower, then power cycle once; if E3 returns the fan motor, its wiring, or the PCB needs technician service. On Gen 3 the same fault shows as EH 03, and on multi-zone outdoor boards as E8/F5 (outdoor fan).

First checks before service

This page currently documents the safe reset triage. If the code returns, use the linked source manual or a qualified technician for code-specific diagnosis.

1. 1. One-time fault event (power disturbance or transient sensor reading) common DIY

   Check: Power-cycle at the breaker/disconnect (or unplug for CPAP), restore, and run the system while watching for the code.

   Fix: If the code does not return after a full run cycle, the fault was transient — monitor, no repair needed.

2. 2. Fault persists after a clean reset occasional pro only

   Check: If the code returns immediately or every session, note the conditions (startup, heating, after rain).

   Fix: A persisting code points at the component the manual assigns to this code — that repair is technician territory.