How much does it cost to fix Baxi error code E.04 – .01?

Typical repair cost for the Baxi E.04 – .01 fault is £90-160 including labour.

E.04 – .01 High

Baxi E.04 – .01 Fault Code

Q: What does the Baxi E.04 – .01 fault code mean?

Your boiler has stopped working because it cannot correctly measure the temperature of the water leaving the unit due to a faulty internal sensor or wiring.

Also written as E0401 — same fault.

The Baxi E.04 – .01 fault code means: your boiler has stopped working because it cannot correctly measure the temperature of the water leaving the unit due to a faulty internal sensor or wiring.. It appears on 24 Baxi models in our database.

Technical description: Flow temperature sensor short-circuited. Sensor not or badly connected, bad connection or sensor fault.

What causes the Baxi E.04 – .01 fault?

This fault occurs when the boiler's control board receives an impossible electrical signal from the sensor that monitors the hot water leaving the unit. The most common reason is that the internal sensor has suffered an electrical short-circuit or the delicate wiring connecting it to the main computer has become loose or damaged.

Typical repair cost £90-160 (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 E.04 – .01 fault code

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

Source

Baxi E.04 – .01 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 27 April 2026