AM040 Medium

Baxi AM040 Fault Code

The Baxi AM040 fault code means: your boiler is struggling to accurately measure the temperature of the hot water it is producing, which may cause your taps to run cold or fluctuate in temperature.. It appears on 1 Baxi model in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: Outgoing DHW temperature check °C
Typical repair cost £120-220 (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 AM040 fault code

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

Source

Baxi AM040 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