Bosch Mini Split P1 Error Code

What P1 means

P1 means high or low voltage protection on Bosch Climate 5000 Gen 2 single-zone systems (2 lamps flashing; Gen 3 equivalent PC 01) - the outdoor unit detected voltage or current outside the safe operating range. Heat Pump Answers: check the breaker and supply; persistent P1 goes to an electrician or technician. On a multi-zone outdoor board, P1 instead means high-pressure protection - a refrigerant-circuit fault, not a voltage fault.

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.