Ford Focus Owners Manual: Principle of operation

Engine immobiliser

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Coded keys

Note: Do not shield your keys with metal objects. This may prevent the receiver from recognising your key as a valid one. Note: Have all of your remaining keys erased and recoded if you lose a key ...

More about Ford Focus:

Ford Focus Special Tool(s), General Equipment, Material
Special Tool(s)  Aligner, Clutch Disc 308-006 (T71P-7137-H) Aligner, Crankshaft Sensor 303-1417 Alignment Plate, Camshaft 303-465 (T94P-6256-CH) Compressor, Piston Ring 303-D032 (D81L-6002-C ...