This light is properly called the Malfunction Indicator Light, so it’s kind of like a check-engine light. It’s telling you there’s something not right somewhere on the car and that you need to scan the car to get a more focussed idea of what the problem is.

The message is not to try to cancel the light and ignore it, because it could be being triggered by something you need to attend to promptly before further damage is done.

Most workshops will have a code-reader that plugs into the car and talks to the car’s computer to learn exactly what the root cause of this problem is. In many cases on a Jeep, the MIL will be triggered by a problem with the fuel and/or emissions system, typically a dud oxygen sensor, a loose fuel cap or even a tiny leak in the fuel system.

Once the technician has checked what fault codes are present, they can usually use the same code reader to cancel the MIL.

Many cars don’t appreciate having the brake and throttle peal pressed at the same time. It’s partly a response to cases of pedal error in the USA many years ago that almost bankrupted some car companies via legal cases brought by owners who had pressed both pedals and had their car rocket through a wall or into a shopping centre. The US courts called it Unintended Acceleration. The rest of the world called it Pedal Error.

In any case, if you do press the brake and throttle pedal together, the throttle may – as you have noted – become unresponsive. But it should return to normal operation within a few seconds. You claim not to be pressing both pedals at once, but sometimes, even a light, unintentional brush of the brake pedal is enough to send the car into no-throttle mode.

That said, you could have a vehicle that incorrectly 'thinks’ you’re pressing both pedals when you are not. In that case, the sensors that detect pedal pressure may need to be changed. You could also be dealing with a car with a faulty body computer – the brain that links all these functions together cohesively.

It kind of all depends on why you’re considering changing the wheels and tyres on your vehicle. If it’s for aesthetics, then go right ahead, but bear in mind that ride quality will likely suffer as a result. That’s because an 18-inch tyre will (typically) have less sidewall depth than a 17-inch tyre. And a tyre’s sidewall plays a huge part in how a car feels to ride in. Fundamentally, the smaller the sidewall, the harsher the ride will be.

In an off-road sense, you’re probably better off sticking with 17-inch wheels, too. By fitting an all-terrain tyre, you’ll improve your off-road grip. That said, all-terrain tyres (once restricted to smaller sizes) and now available in 18, 19, 20 and even 21-inch fitments.