Great Wall Ute Range

In order to find the remedy, you first need to know the cause. On this vehicle, the P0300 code indicates a misfire in one or more of the cylinders of the engine. In the majority of cases, this can be traced to a faulty coil, high-tension lead, spark plug, computer or even the fuel system. The warning shows that one of the cylinders is not firing as cleanly as it should be, so those are the basic thigs to start with. The problem could be as simple as moisture inside one of the coils or its fittings, or even a simple dodgy spark plug. If that’s the case, replace all of them, rather than just the one that’s faulty, as the rest are also likely to be getting towards the end of their life.

You’d be surprised at how much load an air-conditioner places on an engine, especially when it’s idling and not making much power or torque. It can certainly be enough to make the engine labour and drop revs, forcing it down to a speed where it can no longer idle smoothly; almost as if it’s trying to stall.

Carmakers get around this by programming an idle-up function into the car’s computer. This detects that the air-con has been switched on and will then tell the engine to idle a little faster to keep everything running smoothly. If this idle-up function is not working, you can get the precise symptoms you’ve described. However, if this is the cause then make it GWM’s problem to put right, as it amounts to a fault and should be covered by the new-car warranty.

The failure to load the sensors is probably a centralised computer problem, since it’s more than one sensor (it would be an amazing coincidence if three sensors died at once). Either the Bluetooth connection is iffy, or there’s a software problem with reading what the sensors are saying.

I’m unsure how Great Wall can call the tyre-pressure sensor monitoring system a consumable. Yes, things like brake pads, tyres and batteries are considered consumables and not covered by a new-car warranty, but the tyre pressure monitoring system should last the life of the vehicle and is an important safety feature. I’d be ignoring the dealer and talking directly to GWM’s Australian customer service department and asking the tough questions. Australian consumer law is pretty clear on matter such as this one.