English to Serbian Other Automotive / Cars & Trucks

In new cars, a lot of the engine management is controlled by an ECU - electronic control unit. This little computer controls the ignition, the brake systems, and sometimes can even make pretty significant changes to the way a car works. In the BMW M5, for example, the "M" button on the steering wheel unleashes another 100 horsepower by letting the on-board computer make changes to the way the engine output is generated.

Back in the days of carburetors, ignition timing belts and all that lark, there was no such thing as software failure. The most intelligent piece of electronics in an engine would be the little timing relay that would control the blinking speed of the indicators. And at least the blinker can would have a healthy 'click-click' sound. No click-click, no indicators, and you know something is wrong.

But of course, as with all computers, things sometimes go wrong. All computers crash. All software has bugs. As such, many ECU units are fitted with a 'limp home mode'. When it detects that something semi-serious is wrong, it enters the limp mode, which means that the engine won't rev beyond a pre-programmed speed, you can't accelerate very fast, or you may indeed be speed-restricted to 40 mph or similar. Bad? Well, no, not really: The alternative would be to either let you drive at regular speeds, with the danger of letting you trash your car (expensive repair, means happy repair people, but angry driver), or stopping you from going anywhere (expensive recovery and stranded on the side of the road means happy recovery company, but angry driver).

Limp home mode, then, is a fantastic invention.