Please explain engine immobilisers

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Car chained up

An engine immobiliser, as the name suggests, is a security system designed to prevent the engine being run long enough for the car to be stolen. They’ve been a requirement for all new cars in Australia since 2001, so it is very likely your vehicle has one fitted.

Most of the systems work with a transponder chip embedded in the key or fob. When the key is turned or the start button pushed, the car’s computer sends a coded signal out. If the chip in the key responds with the correct code then the computer will allow the car to continue running. If the code is wrong, or no code is received, the engine will be cut. On many cars the engine may run for three or four seconds before cutting out. The key has to be coded individually to the car, which makes getting new keys quite a rigmarole that typically needs access to the car and an already coded key. It’s also expensive, so when buying a new car be sure to ask the dealer for an extra spare key as a sweetener.

If your car is pre-2001 and has an aftermarket system fitted, have it checked out by an auto electrician as part of your service routine.

Because immobilisers are so effective, keys are a hot target for thieves. More than 70 per cent of late-model cars thefts use the car’s own keys. Increasingly, homes are being burgled to gain access to car keys, so make sure you have sufficient home security and don’t leave keys lying around.

Written by Nicholas Platt
May 23, 2017