Induction hob shows E4 and the affected zone cannot be used.

Safety first: Isolate the hob at the mains. Power components can retain charge; wait several minutes before touching internal parts.

Diagnostic steps (technician level):

• Remove the hob and access the induction power module for the affected zone.
• Visually inspect for burnt tracks, cracked components, or bulging capacitors.
• Disconnect the induction coil and test its resistance; it should be low but not shorted to earth. Check insulation with a megohmmeter if available.
• Test the IGBTs/MOSFETs on the power board with a multimeter in diode mode for shorts between collector/emitter (or drain/source).
• Inspect the wiring harness from the board to the coil for chafing or melted insulation.

Remedy:

• Replace any shorted IGBTs or, more commonly, the complete induction power board for that zone.
• If the coil is shorted or physically damaged, replace the induction coil assembly as well.

This repair should be carried out only by a qualified engineer due to the risk of electric shock and fire if incorrectly repaired.