How much does it cost to fix Worcester Bosch error code Fault 02 / 42?

Typical repair cost for the Worcester Bosch Fault 02 / 42 fault is £90-180 including labour.

Fault 02 / 42 High

Worcester Bosch Fault 02 / 42 Fault Code

Q: What does the Worcester Bosch Fault 02 / 42 fault code mean?

Your boiler's main control chip is not making a proper connection, meaning the 'brain' of the appliance cannot communicate correctly.

Also written as FAULT0242 — same fault.

The Worcester Bosch Fault 02 / 42 fault code means: your boiler's main control chip is not making a proper connection, meaning the 'brain' of the appliance cannot communicate correctly.. It appears on 1 Worcester Bosch model in our database.

Technical description: Internal fault: Code switch on IPM in intermediate position.

What causes the Worcester Bosch Fault 02 / 42 fault?

This fault occurs when the boiler's memory chip, known as a code plug, is not physically seated correctly or has developed a hardware failure. The most common reason is that the chip has vibrated loose or the main circuit board can no longer read the specific programming required to run your boiler safely.

Typical repair cost £90-180 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Worcester Bosch models that show the Fault 02 / 42 fault code

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

Greenstar CDi Compact Repair: £90-180

Source

Worcester Bosch Fault 02 / 42 fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026