Thanks for your post and excellent photos.
On the N12 engine, I found it wasn't necessary to remove the heat shield. The 3 bolts securing the front face of the heat shield are also a real fiddly to reach too.
The new pre-cat O2 sensor comes with a male electrical socket which is fixed to the metal bracket. To unplug the cable, press the visible clip on front facing one side of the FEMALE plug and then gently ease it off by pulling upwards - make sure you grip the plug and don't try to pull on the wires! Then you will probably need to use a large flat bladed screwdriver to carefully lever the connector against the bracket, to separate them.
Now remove the 10mm bolt which secures the bracket to the oil filter housing. The post-cat cable will still be attached to the bracket, but you should be able to move the bracket and cable to one side, to improve access to the O2 sensor.
It wasn't too difficult to remove the O2 sensor using a Laser oxygen sensor socket, extended length extension bars, and 12" wrench.
We bought a new Bosch pre-cat O2 sensor from EuroCarparts for £115. Note that ECP do not list actual Bosch part numbers on their website, but Bosch do have a lambda sensor catalogue PDF which you can download to check exactly what is needed. I've uploaded a jpeg from their 2015 catalogue.
www-DOT-bosch-lambdasonde-DOT-de/en/downloads/catalogue_2014_2015.pdf
The actual Bosch part number is only printed on the new O2 sensor's cardboard box.
fwiw, for 1.6 N12:
long code 0258017217
short code LS17217
(We did find a code printed on the electrical connector on both old and new O2 sensors matched, but it didn't correspond to any Bosch catalogue part number.)
As far as I can tell from the catalogue, Bosch do not appear to make the post-cat sensor, and yet ECP offer a Bosch post-cat sensor. NTK may be the OEM for the post-cat sensor.
Forgot to add P2414 O2 sensor error kept appearing immediately after starting engine after erasing it a few journeys earlier. Engine with 40k miles ran fine. New sensor resolved problem.
On the N12 engine, I found it wasn't necessary to remove the heat shield. The 3 bolts securing the front face of the heat shield are also a real fiddly to reach too.
The new pre-cat O2 sensor comes with a male electrical socket which is fixed to the metal bracket. To unplug the cable, press the visible clip on front facing one side of the FEMALE plug and then gently ease it off by pulling upwards - make sure you grip the plug and don't try to pull on the wires! Then you will probably need to use a large flat bladed screwdriver to carefully lever the connector against the bracket, to separate them.
Now remove the 10mm bolt which secures the bracket to the oil filter housing. The post-cat cable will still be attached to the bracket, but you should be able to move the bracket and cable to one side, to improve access to the O2 sensor.
It wasn't too difficult to remove the O2 sensor using a Laser oxygen sensor socket, extended length extension bars, and 12" wrench.
We bought a new Bosch pre-cat O2 sensor from EuroCarparts for £115. Note that ECP do not list actual Bosch part numbers on their website, but Bosch do have a lambda sensor catalogue PDF which you can download to check exactly what is needed. I've uploaded a jpeg from their 2015 catalogue.
www-DOT-bosch-lambdasonde-DOT-de/en/downloads/catalogue_2014_2015.pdf
The actual Bosch part number is only printed on the new O2 sensor's cardboard box.
fwiw, for 1.6 N12:
long code 0258017217
short code LS17217
(We did find a code printed on the electrical connector on both old and new O2 sensors matched, but it didn't correspond to any Bosch catalogue part number.)
As far as I can tell from the catalogue, Bosch do not appear to make the post-cat sensor, and yet ECP offer a Bosch post-cat sensor. NTK may be the OEM for the post-cat sensor.
Forgot to add P2414 O2 sensor error kept appearing immediately after starting engine after erasing it a few journeys earlier. Engine with 40k miles ran fine. New sensor resolved problem.
