It’s very possible that the continuous clicking noise you can hear is the central locking trying to lock the vehicle but, for some reason, not achieving the desired result. That could be because there’s a misalignment between the bits that actually physically do the locking. If these aren’t aligned correctly, they can’t physically interlock and lock the vehicle. And when that happens, they keep trying which causes the continuous noise you’re hearing.

But the cause could also be a problem with the car’s body computer. This computer is responsible for all sorts of tasks including the stereo, air-conditioning, wipers, lights and, of course, the central locking. If the computer loses the plot it can easily convince itself that the car is unlocked and needs to be locked. Over and over again.

However, the body computer also takes its cues from a variety of sensors around the car, including little switches in the central locking to tell it that the car is locked or unlocked. If one of these fails you could get similar symptoms.

But before any of that – and it sounds pretty basic – walk around the car and make sure all the doors, windows and engine cover are closed properly, as a slightly open window or ajar door will often confuse a central locking system.

The most likely cause of this is a Diesel Particulate Filter (DPF) that is either blocked or on its way to becoming blocked and needs cleaning. Soot build-up in a DPF can restrict the flow of exhaust gasses, at which point you might also find the car’s computer will limit performance to avoid doing damage to the engine.

You can either try to force the DPF to regenerate, or you may have to have the DPF manually cleaned or even replaced.

The other possibility is a problem with the Exhaust Gas Recirculation (EGR) valve which can also become clogged with soot and affect the vehicle’s performance and emissions. Either way a check up at a workshop with the appropriate scanning equipment is necessary.

Conventional wisdom suggests that a modern electronic fuel-injection system is smart enough not to flood an engine when starting., However, experience tells me that sometimes, you can get excess fuel into the engine if it doesn’t fire straight away. However, if you keep trying to start it, that fuel should pass through the engine, and it should eventually fire. So, I’d say your problem is something else.

A mechanic would probably start by checking things like whether the fuel pump is operating, the fuel and air filters, fuel pressure and whether the fuel injectors are pulsing when they should be. Your problem is likely to be a shortage of fuel rather than too much of it, so checking the fuel delivery pressure and rate is a critical step.