Engine idle high when AC is on
 

Hey guys my name's Chris and I just bought a pre owned 2013 LR4 HSE Lux.

The slight issue I'm facing (not sure if it's even an issue which is why I'm asking) is that when I switch on the AC, engine idle goes from the normal of about 600rpm to somewhere between 1000 and 1200rpm when the car is in neutral.

When the car is in gear the rpms drop to about 800 or a little bit above that and what's annoying is that you really have to keep your foot planted on the brake in order to prevent the car from moving (as opposed to just having to "touch" the brake pedal to keep the car at a standstill when it's idling at the normal 600rpm when the AC is off).

I wonder if this is a problem with my car or if it is something common that can be seen on all cars.

Any help or advise would be greatly appreciated.

It's pretty common for vehicles to increase the rpm with a/c on, but it's probably more pronounced with an engine pumping out as much torque as the LR4 does. As the a/c is belt driven off the engine, when it's turned on it puts an extra load on the engine and rpm wants to naturally drop. With the engine being computer managed and intended to keep output within a certain band, the rpm is increased to counteract the load of the a/c.

I think that's where the old argument about a/c 'On' reducing mileage comes from.