I turned the car on without the 2nd lambda sensor, the one behind the CAT and I got yellow check engine and I'm wondering if the code will go away when I connect the 2nd sensor back in or I need to somehow clear this code? and how to do it? I tried thru torque and ebay BT OBD2 but I can just list/read fault codes and didn't find an option for clearing them.

Now why I did this stupid thing. Well because I trusted someone that told me the second one only checks for CAT and taking into consideration I have bluefin stage 2 that has that option off cos usually I use on this car with miltek de-cat and I can't remove the bloody sensor from it cos it's stuck. I put the original CAT on the car just to go thrue MOT but obviously I need the second sensor also and not just plug the hole.

thanks

my engine light has just come on, seems to be orange in colour anyway since the car is running great will this be a classif sensor on the blink, lambda one or the other ?

hi mate.
do you have any kind of OBD2 adapter (wi-fi, BT, USB) so you can use some software on your smartphone (torque, Car gauge pro, FORScan Lite) or your PC (FORScan) to check the problem?
that's the first step IMO.

you can get cheap OBD2 adapters of ebay for a few quid.
I even manages to clear the code using this cheap one what I was afraid I wont be able to do cos these are cheap Chinese clones of the devices so sometimes they lack options.

cheers.

edit: how many km you have on your car? As I understand original lambda part (2nd one), which is BTW Bosch part No. 0 258 006 713, and you can get it directly from Bosch or auto part stores for 2-3 cheaper than in Ford shops, should go for at least 150 000km.

this is my original lambda probe (2nd one, after the CAT, called post-cat or downline if I'm not mistaken):

Hi thanks

yes I have a cheap is one, it read as one fault and one code then when I scrolled to codes it said "Pere:oo" so not sure if it was reading it correct or couldn't read it, in the past it has read correctly with the usual "P" and following numbers when I was having trouble with my throttle body.

try different software to check for error.
using smartphone or pc?
your fuel consumption is normal, cos that's the main thing that goes when sensor is bad AFAIK?

just a handheld plug into the OB2, fuel is great car not been going anywhere for 4 months !