GM003 Emergency

Baxi GM003 Fault Code

The Baxi GM003 fault code means: your boiler is detecting a flame inside the unit when it shouldn't be, which indicates a potential issue with the internal electronics or ignition system.. It appears on 1 Baxi model in our database.

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

Technical description: Flame detected (0: Not detected, 1: Detected)
Typical repair cost £150-300 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Baxi models that show the GM003 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Baxi GM003 fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026