courtesy of Clowntype
replaced the g28 sensor (dealer £150, ecp £90(they do a cheaper one but not worth the saving in my opinion))
tools
sockets 10mm,13mm longwall, 16mm,17mm big sockets 3/4 drive various extensions
allen key 5mm to fit in end of socket
long flat screwdriver
put jack under bellhousing/engine join
undo 3 starter motor bolts
(take 2 off 13mm nuts off that secure cables/clips(one on top bolt one on front bottom bolt)
then you have 2 off 16mm bolts(top and bottom to rear of car, and 1 off 17mm closest to front of car)
jack up approx inch
remove 17mm bolt from top of engine mount(long extension in from the top)
take 10mm bolt off bracket( holds cable/pipe control clip)
bit of jiggery pokery and that bracket will come out through the top allowing you straight in to the sensor
i would take the time to clean the area all around the sensor so you're not pushing crap back into the hole with the new sensor
then you need a 5mm allen key on a medium extension go over the front crossmember and under the 2 hoses, you'll see the position off your new one if you're not sure
undo the bolt and then you'll need a bit of leverage against the engine just to 'pop' the sensor out (long flat screwdriver should do it)
then remember the routing of the cable when you remove it for putting the new one in.
put the new one in the hole it should be loose, spin it to locate the bolt screw the bolt in until it just takes the tension then use a lever against the cross member to 'pop' it in(i used a long socket extension) then tighten the screw
assemble in reverse
DONE