Can someone please help as I'm going crazy with this damn Lambda Sensor. My 2002 Impreza 2lt Turbo WRX failed it's MOT on emissions so I got it put on a machine. They said that the front Lambda needed replacing which I got through Just Lambda with a direct replacement:
250-54004 which was £115 instead of £285 from Subaru. The problem is now that it's fitted it's made no difference what so ever and has failed again. Has any one got any ideas as I'm completely confused? and gutted that I've spent £115 + £55 fitting for no reason. Nice One.

 

this was the one on the corner at the front you changed

 

The garage changed the wrong one 1st on the pipe under the drivers door but when I told them that there is one at the front they changed that one. I hope that it's the one that you mention on the corner.