How much does it cost to fix boiler error code GM004?

Typical repair cost for the boiler GM004 fault is £150-300 including labour.

GM004 High

Boiler Fault Code GM004

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code GM004 appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has detected an issue with the valve that controls the gas supply, meaning it cannot ignite safely to provide heating or hot water. (As reported on Baxi 400 Combi 2)

Pick your boiler brand for the GM004 fix

Baxi GM004 1 model

Source

Information for the GM004 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 7 July 2026