Baxi fault code E.04.23 means communication internal stoppage. Baxi lists this wording for applicable Combi 2 and System 2 boilers.
The boiler’s controls rely on internal electronic communication to coordinate safe operation. E.04.23 means that communication has stopped at a point the appliance monitors, so the boiler may stop heating and hot water. The code does not identify a particular board, cable or connector as faulty.
What does Baxi E.04.23 mean?
Modern boilers use connected controls to manage requests for heat, monitor safety conditions and operate components in the correct sequence. An internal communication stoppage means the expected exchange of control information has not continued normally.
The safe response may be a shutdown or lockout. The display tells you the type of problem recorded, but a qualified engineer needs the exact model, fault history and Baxi service information to locate the cause.
Which Baxi boilers use E.04.23?
Baxi includes E.04.23 in its current Combi & System 2 error-code group. The listed ranges are the Baxi 200, 400, 600 and 800 Combi 2, the Baxi Assure 500 Combi 2, and the Baxi 600, 800 and Assure 500 System 2.
Other Baxi boilers can use different displays or code meanings. Confirm the complete model name from the exterior or the appliance paperwork and use its matching user guide.
Does E.04.23 identify the failed component?
No. Baxi’s public description does not name the internal communication route or component involved. It would be misleading to assume from the code alone that the main control board, a cable or a particular device needs replacing.
An engineer may need to review stored faults and perform model-specific electrical and control checks. Those tests should determine the repair rather than a guess based on one display message.
Is E.04.23 the same as E.04.29?
Baxi’s current error-code table gives the same short description—communication internal stoppage—for E.04.23 and E.04.29. They are still separate recorded codes.
Do not shorten the message to “communication fault” when booking. Giving the complete E.04.23 code helps the engineer consult the correct technical sequence for the exact model.
What can you safely check?
You can collect useful information without opening the boiler:
- Write down E.04.23 exactly, including the punctuation.
- Confirm the full model name from the casing label or paperwork.
- Note whether heating, hot water or both have stopped.
- Record the visible system-pressure reading.
- Check whether the room thermostat or programmer display is powered normally.
- Note whether there has been a recent power cut or electrical work.
- Record any other code shown before or after E.04.23.
- Note whether the code remained after one reset permitted by the exact user guide.
Do not remove the casing, reseat plugs, test voltages, touch wiring, change control-board settings, perform a factory reset or enter installer menus. Internal boiler electronics can involve mains voltage and safety-critical controls.
Can you reset Baxi E.04.23?
Check the user guide for your exact model. If it permits a homeowner reset, one careful attempt may be reasonable when there is no smell of gas, carbon-monoxide alarm, water leak, visible damage or unusual noise.
If E.04.23 remains or returns, stop resetting and arrange a repair. A reset can restart the control sequence, but it cannot repair an unreliable connection or electronic fault.
Could a power cut cause the code?
A recent interruption is useful information to tell the engineer, but it does not prove the cause. If the code stays after power has returned and the one permitted reset has been tried, the appliance still needs professional attention.
Do not repeatedly switch the boiler supply off and on. Frequent power cycling is not a substitute for checking the recorded internal communication stoppage.
Can you keep using the boiler?
Do not try to force the boiler to run while E.04.23 is displayed. Its controls have reported a loss of internal communication and may not be able to complete the normal operating sequence.
If the code clears once but returns later, treat it as an intermittent unresolved fault. Record when it happens and arrange repair.
When is urgent action needed?
If you smell gas, suspect carbon monoxide or hear a carbon-monoxide alarm, follow current Gas Safe Register emergency guidance immediately. Do not operate electrical switches or wait for a routine appointment.
If there is smoke, scorching, a burning smell, sparking or water near electrical parts, keep away from the appliance and seek urgent professional advice.
What will an engineer do?
A qualified engineer will confirm the model, review the stored fault information and follow Baxi’s service procedure. They can test the relevant communication and control circuits safely, identify the actual cause and complete the appropriate repair.
When booking, provide the exact code, model, visible pressure, any recent power event and what stopped working. Our boiler help guides explain other messages, while internal electrical checks remain professional work.
Is your Baxi showing E.04.23?
Book Incredaboil’s fixed-price boiler repair for a clear price and an engineer visit aimed at fixing the communication fault and restoring reliable operation.
Quick answers about Baxi E.04.23
What does E.04.23 mean on a Baxi boiler?
It means the boiler has recorded an internal communication stoppage.
Does E.04.23 mean the main PCB has failed?
No. The public code description does not identify one failed component. Proper testing is needed.
Can I reconnect a loose plug myself?
No. Keep the casing closed and leave internal connectors, wiring and voltage checks to a qualified engineer.
Can I reset E.04.23?
Follow the exact model guide. One permitted reset may be reasonable when no warning signs are present, but do not repeatedly reset a returning code.
Is E.04.23 the same as E.04.29?
Baxi gives both the same short description, but they are separate codes. Report the exact one shown.