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D1 204 FAULT CODE
Worcester Bosch

Boiler Identification Module Fault

Medium Severity Engineer Required

The boiler's identification module (SCB) is not communicating correctly with the main PCB. Usually occurs after PCB replacement.

Step-by-Step Fix Guide

  1. Step 1

    This is almost always a post-service fault

  2. Step 2 Engineer only

    The engineer who last worked on the boiler should check the SCB connections

Gas Safe Reminder

Work on gas appliances must be carried out by a Gas Safe registered engineer. The steps above cover safe checks a homeowner can perform - any internal component replacement requires a qualified professional. If in doubt, always call an engineer.

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