Low
A.00.34 on Baxi 400 Combi 2

Your boiler is looking for an outdoor weather sensor that it cannot find or that has stopped communicating with the system.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Outdoor temperature sensor expected but not detected

Shared across the 400 Combi 2 range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Check if an outdoor sensor was recently installed or removedInspect the sensor wiring outside for any obvious damage or loose connectionsTurn the boiler power off and back on to see if the error clears

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Related fault codes

A.00.33View →E.160View →

All 110 fault codes on the 400 Combi 2

Seeing a different code? Every code this model can display, in one place.

A.00 .28A.00 .29A.02 .37A.02 .45A.02 .46A.02 .48A.02 .49A.02 .54A.02 .76A.02.06A.02.36A.02.55AM001AM010AM011AM012AM014AM015AM016AM018AM019AM024AM027AM036AM037AM040AM091AM101AP073AP079BM000CM030CM120CM190CM210CM280CP000CP020CP210CP230CP470CP480CP490CP780DM001DM002DM005DM009DM019DM029DP430DP440E.00.04E.00.05E.00.16E.00.17E.00.20E.00.21E.01.04E.01.12E.01.17E.01.20E.02 .13E.02 .35E.02 .39E.02 .47E.02.17E.04 .29E.04 .54E.04.01E.04.02E.04.03E.04.08E.04.10E.04.12E.04.13E.04.17E.04.18E.04.23GM001GM002GM003GM004GM007GM008GM012GM013GM044H.00 .81H.00.42H.01.00H.01.05H.01.08H.01.14H.01.18H.01.21H.02 .70H.02.00H.02.02H.02.03H.02.04H.02.05H.02.07H.02.09H.02.10H.03 .54H.03.00H.03.02H.03.05

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