P.01 Medium
Boiler Fault Code P.01
Also written as P01 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code P.01 appears across 1 boiler brand and 29 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has failed while running a specific test used for commissioning or high-power performance checks. (As reported on Vaillant ecoTEC plus)
Pick your boiler brand for the P.01 fix
Source
Information for the P.01 fault code is sourced from the official service / installation manual for each model that displays it. Read more about how we source fault codes →
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026