Haval SUV Range

There’s about a million possible causes of this, but most mechanics would probably make a check of the electric fuel pump one of their first moves. Modern electric pumps have a finite lifespan and when they die, it can be very sudden. You can try a quick test for yourself at home, too. When it’s nice and quiet, turn the ignition until the dashboard lights come on. At that point, you should be able to hear a faint hum or buzz. That’s the electric fuel pump switching on to supply fuel to the engine. If you can’t hear it humming away, chances are it’s either dead or a fuse or other electrical problem has stopped it in its tracks.

There’s also the chance that the failure to start is related to the car’s ignition system which, again, could have any number of causes. Old spark plugs, blown coil-packs, a dud sensor or even a broken wire could be the problem.

The HDC refers to the Hill Descent Control feature that allows the vehicle to crawl down a steep slope off-road without the driver applying the brakes. This function uses the car’s braking and ABS systems to operate, so any fault with it has serious implications for the vehicle’s overall safety.

You may have a dud sensor or something wrong with the wiring, electronics or even the hardware. Either way, an electronic scan should give you a few clues as to what’s causing this fault message to show up. Sometimes something as simple as a battery with low voltage can cause error messages like this to appear. But don’t ignore it; these are important safety systems and you need to know they’re working properly.

Any time a mechanic sees an illogical pattern of faults like these all at once, their suspicions are always drawn to the body computer. This computer controls all the functions you’ve mentioned as well as hundred more, and when it goes on the fritz (as computers are wont to do) you can suddenly get all sorts of weird behaviour, just like you’re reporting.

Take the car to an auto electrician who might be able to make sense of what could be a complex wiring issue. But the smart money says body computer every time. These can be replaced by a new computer, second-hand ones from a wreck and sometimes even fixed by very clever people. If the auto electrician can’t offer any advice, get online and see what help is out there.