BMW Front

How Your Immobiliser, ECU And Key Work Together To Secure Your Car

With some technical aspects of modern vehicles, we simply take them for granted. Take using a fob to casually lock and secure your vehicle as you walk away. It’s easy and convenient, but do we really know the mechanics at play?

Similarly, your immobiliser, ECU (Engine Control Unit) and key probably fall in to this bracket. We all know that an immobiliser is there to protect the vehicle from theft, but what is it exactly, and how does it work with the key and ECU to protect your vehicle?

The immobiliser, mandatory in cars in the UK since 1998, uses a code in the ignition key that is then checked against the vehicle’s ECU, which regulates fuel and the starting mechanism. If this isn’t activated, the car cannot be used.

From here, technology has evolved to give some vehicles a delayed start for security, and to allow them to communicate with security companies to show when someone unauthorised is attempting to use the vehicle. ECUs also record information in modern vehicles, and can be used to record different statistics on driver information and vehicle location. These can then be used in insurance investigations and warranty claims.

The downside of all this technology is that it can be prone to faults, as with many electronic systems in cars. Common faults include damaged and corroded wiring, errors with sensors, keys that can lose their coding imprint, and corrupted ECU units. The first sign, as with most faults, is usually warning lights, but other symptoms may include an apparently ‘dead’ ignition despite all the controls lighting up, or the engine turning over but not starting.

Some simple fault finding can include testing the keys with another key for that model (a ‘swap test’), or similarly testing or replacing the batteries in the key fob if you’re using a remote fob, to ensure that this isn’t causing the problem. It could even be a battery issue, in which case testing another battery could be worth a try, to narrow down the cause of the issue.

If simple tests like these can’t locate the problem, then it may be time to call in the experts. Autotronics uses bench testing on a range of auto electronic equipment to find and fix common faults. Our service includes express shipping and fast turnaround times of between 1 and 4 working days. It is always better value to have electronic components repaired with us than to pay for costly dealership repairs, so use Autotronics to get your car running smoothly again.