A COMMON mistake drivers make with their car keys could lose you hundreds off your motor's value.
Most cars have two sets of keys - the modern "keyless" lock and the old-school car key.
They come as a pair so you're not locked out if your motor's keyless security crashes.
Losing one of the keys could knock more than £1,000 off your car's value.
Motorpoint expert John Hood told the : "The average cost to replace a key is around £240.
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"But a new remote or keyless entry key for a modern vehicle could cost you more than £1,000.
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"However, without both sets of keys, expect to see anywhere between 5 to 10 per cent less for your vehicle."
The expert said putting your car up for sale without both keys could slash its value by up to £1,530.
If you lose the back-up metal car key, flogging the motor could be impossible.
It comes as drivers are only just realising what happens when you press and hold unlock on the key fob - and it could affect your car.
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