46/58 High

Grant 46/58 Fault Code

Also written as 4658 — same fault.

The Grant 46/58 fault code means: your boiler's control system has detected a potential communication error or a sensor fault that is preventing it from firing up correctly.. It appears on 1 Grant model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: 46/58
Typical repair cost £150-300 (including labour)

Engineer required

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

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Grant models that show the 46/58 fault code

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

Source

Grant 46/58 fault code information on this page is sourced and cross-checked against the official Grant service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026