How much does it cost to fix Baxi error code E.04 – .02?

Typical repair cost for the Baxi E.04 – .02 fault is £90-160 including labour.

E.04 – .02 High

Baxi E.04 – .02 Fault Code

Q: What does the Baxi E.04 – .02 fault code mean?

Your boiler has stopped working because it can no longer accurately measure the temperature of the water leaving the unit.

Also written as E0402 — same fault.

The Baxi E.04 – .02 fault code means: your boiler has stopped working because it can no longer accurately measure the temperature of the water leaving the unit.. It appears on 24 Baxi models in our database.

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

What causes the Baxi E.04 – .02 fault?

This fault occurs when the boiler's control board loses communication with the sensor that monitors the temperature of the water sent to your taps and radiators. The most common reason is that the sensor has developed an internal electrical failure or the wiring connecting it to the main circuit board 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 – .02 fault code

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

Source

Baxi E.04 – .02 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