Kelvo, I agree. The picture definitely shows it connected post shunt so should be the equivalent of being connected to the body for all intents and purposes.
Printable View
Hi Kelvo, and while the connections are made after the sensor, any additional current coming from those cables will still have to use the battery’s earth strap ( cable ) as there negative return to the alternator. This will result in a voltage drop ( small or large ) in the earth strap and will effect the accuracy of the sensors reading.
The closest you can safely connect to the cranking battery’s negative ( - ) terminal, is where the earth strap bolts to the inner guard.