Jaguar XF 2.2 Diesel 2014. Just had the car serviced a couple of weeks ago and mechanic said there's about another 12 months left in my brake pads as my annual mileage is about 5K. Warning light came on yesterday but how can you distinguish if the warning light refers to front or rear pads?

 

You can't.
You have no choice but to manually examine the pads.
The low pad warning sensors are notorious for either going off when there is plenty of pad left or not going off when the pads are excessively worn, you simply cannot trust them.

 

^ bingo! I hate the sensors in the Jag and range rover. When i replaced my front pads, the sensor never went off nor were there noise (when the tab starts rubbing rn the rotor), and to my surprise the padding left was about 1mm. The rear sensor worked however, sensor went off at 3mm.

My 2016 range rover also had the exact same experience. I also hate the fact there is only 1 sensor for the fronts and 1 for the rears.

 

I have this same question on my 2010 xf. So there’s no way of knowing if the front or rear pads are the reason for the message?

What is is the mm size of pads that are still in good condition?

 

There is only one way of knowing - remove the wheels, undo the calipers, remove the pads and actually LOOK at them!
According to the Workshop Manual the low pad warning is supposed to come on when the pad (inner LHF or inner RHR) is down to 25% of new thickness, which is approximately 3 mm for the front pad and 2 mm for the rear pad, so plenty of safety margin.
But the warning sensors are notoriously problematic so the actual pad thickness and condition could be anything from "plenty thick and good" to "down to the backing plate" to "crumbling and about to fall apart". Again, do not trust these sensors, inspect the pads yourself to check their thickness and condition!

 

Same issue. Found out the sensor wire was rubbed apart. I Solder the wire back together

 

You have a lot hate for something that didn't exist at all in cars that long ago. How about you just have your car inspected annually like everyone use to do to know if your brakes are worn and try to rid yourself of all this incredible hate that you have built up inside of you that is slowly killing you?